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Speech processing for under-resourced languages is an active field of research, which has experienced significant progress during the past decade. We propose, in this paper, a survey that focuses on automatic speech recognition (ASR) for these languages. The definition of under-resourced languages and the challenges associated to them are first defined. The main part of the paper is a literature review of the recent (last 8 years) contributions made in ASR for under-resourced languages. Examples of past projects and future trends when dealing with under-resourced languages are also presented. We believe that this paper will be a good starting point for anyone interested to initiate research in (or operational development of) ASR for one or several under-resourced languages. It should be clear, however, that many of the issues and approaches presented here, apply to speech technology in general (text-to-speech synthesis for instance).
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

ab c!"#d
a Laboratory of Informatics of Grenoble, France
b North-West University, South Africa
c SPIIRAS Institute, Saint-Petersburg, Russia
d Karlsruhe Institute of Technology, Germany
Abstract
                      $    
%&
  '(      %  !              
%!$')(
*%"$
$%&*$*
'(
%+*$ 
'(%
Keywords:      '(  *  
,  
%
1. Introduction
-$ %!
              .    '
(      '  (        *    
%!$/011$
,2!'2!(%!2!
 $ $  * $  
**%
 %3$ 
45*
for under-resourced languages%
!$'('(
$$$%&.
   2!. $%!  #
$Introduction
Section 2*$$45$
%Section 3$*
%" Section 4,$
Section 5$$%6Section 6
$.%
1.1 Languages of the world
7*$$.%6
$.*$
*$*$%
*$*Ethnologue1$*%!
4one that has at least one speaker for whom it is their first language5%
.%
/010.$%!89:
%%$"only a few elderly speakers are still living".+
;**..%!
.$$*<.
*$%
$$%
7$$*"%!
    $*  =   =111  $    *    *  **
'(*%Omniglot3, 
$>111$
>)1$%
&..*4$5*
* $       
Google Translate'/:8=1>=(? search(
=1>=),Siri ASR application (8 languages in 2012), Wiktionary5 (~80 languages in 2012), Google
Voice Search'=0=1>=(%
1.2 Language Extinction
+;*#$%7@7=111A
*$*%3
$$.%*Summer Institute of Linguistics
'+(  6* >000   * B>    $   .B11
B11.:111>1%111.%!
*$#.+%+$0/C
$;.*8C%
[100 - 999] Mio
[100 - 999]
[100,000 - 1Mio]
0
200
400
600
800
1000
1200
1400
1600
1800
2000
875
264
892
1779
1967
1071
344
204
0
308
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> DD $$$ % % D
= DD $$$ % % D % 
: DD $$$ % %
8 DD $$$ % % %# D **      D=):0/D
BDD$$$%$.%D
2$$>11%111.
@7=111A%!
.% E   ',.  E-$ ? .
('*01C;$=11,(
    %!    
'*.(
$$'%%(%
2$  *$ $ $  % 6
*$
$%!%+
              *             
.**%!
$%7
* F )1%111    % 7 :111  
$      F 911 G% 3# .  6  
'6(-73"***
."%
1.3 Good reasons to address less prevalent languages
   *      2 ! '2!(%
2$**
'.($%6
    .                %      
      "                   
 through %  6                *
$%$*
%+$
$%7*.*
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2. Under-Resourced (UR) languages
2.1 Definition
!45* @ $=11:< =118A
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$*..
                *    
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  low-density languages resource-poor languages low-data languages, less-resourced
languages%+$
.*%
.*%3
  *  $ '  7 
*Google SearchGoogle Translate(%7,
'$(%
2.2 Measure the Status of a Language
+ *"        ' 
 9($"*$-!'-$.
  (   '   ( @ $ =11:A%
6"**
*  $  %      $      @  =118A         
*'.
$*       (% @ =118A     
 .7*'/%=D=1(%!
H  >1D=1%    
$*$>1D=1%GG!-!'-$./1
 :8($ )  “Languages in the
European Information Society”$$
!.%!.$
   0 '    $
7+G(%
2.3 Challenges
E 2!  '%%   (    ,
,**%+$
   $  '   $  * ##
$%(%!.,
'$@?=1>>A($
      *$    '%%        @#  =11><   
=110A(%+
**$$
'$$(
.'$(%
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 $ ,     '   *$ (
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2.4 Short History on Under-Resourced Language Research
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' Workshop on Indian Language Data: Resources and Evaluation;
Workshop on Language Resources & Technologies for Turkic Languages; Workshop on Parsing in
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2.5 Language resources
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>=DD%*%D
>:DD$$$%%DE7 D
  '  (                %  
*,$N$$N
        *    $      % 3      $    
?*E    #          *  @#  =11=A%  !   
*.
$$%?*E
*  $        '>11
.(,'('.
.%($%,
?*E        *             '>(    
'=(      ':(
.'8(.'B(
$  '/(    %! 
?*E=>*'G(7G7
77#6?2K EE'#(
 '( $!!!.. H% +
811.*=111.
@#=1>:A$*>8
*.%
             
    ! @ =111A  $# @ =110A    
*-72!'**(@FH=1>:A%
!*
.%
3. Automatic Speech Recognition for Under-Resourced Languages (U-ASR)
3.1 Components of ASR systems
      '(                  %%
,$*$$%
'$
*$('$*$$(
'$..*$$('%%
('%%(%
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$,<
  )11. *(<  * '     $
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@K =1>1A F  -$. 'F-( @ =11=A  H G
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@G=1>=< =1>>A @ =1>=< G.
=1>1A%
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%*
******
%
6=%
$
,$%2GG*
* . * H* @L=11)A%
*$D-*

*  %        * 
.$**$**
*2! >BK>/>9!>)>0 F+=1
L!=>%
3.2 Collecting data for UR languages
:%'(
*%2$
   *     %2 
%+$
>BDD.% %%%. 
>/DD"%%"DP% 
>9DD%% 
>)DD%%.%D 
>0DD$$$/%.%$%D$D 
=1DD.%%D
=>DD%%D$.D*D$DE+7!+3-D&*2DL!%#
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<$*$
%
+   *   
*

  '  *$(%  G        *          *
        <             $
#$'$($*
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  *  $   @E =1>1A< $  *  
$$.*
*       @? =1>>A%   
.%
&4.5,B1.@
=110A***#$.%
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*%!**$*
.%+$
'$**#$(%6
.
%      .   
$*,
@F =1>>A    *   $     $
.
%6'
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+*.<
.   *         %
**'
(@#=11=A<*$.
*  
'**(,%!
$*
@2 =1>1<FH=1>><FH=1>:A * * $
  *  $.  *% +     $. 
*.
%
3         *     
@?>00=A%2$
*

%!*
*%
3.3 Feature processing
+ $ - -$.$  % 6
'GE($$
  '! ( @2. =111A      '-. (
@?#=119AG677%+
GE*$*
*.*$%+
               $      *  
$
*%
$GE$$$
*@.=11/<!=11)A@E=1>>A%@!
=1>=A@!=1>=*A@H=1>=A$
%!
$.$*$
,%+@H=1>=AGE#
  GE        *    +E   %  !    $  
*                      *  *  
@H=1>=*A%
3.4 Acoustic modeling
    *            *          
%2        
%7$#
!@7=11)A<*E@=110A
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*@H2=1>1A
*@#=11><=110A
$@7=1>=A*'GE(
$%7*$
**,
%
*2
G.  G              %  6    
*      '      @?.  =1>>A(      
'$($%$
$***%
2G.G*
@!*=1>=<!*=1>:A<N
            * %
@=1>:A*.$
*45.%*
   '    * @G# =11:A(      
**+E@Q.
=11:A$,%!$.*@=1>:A
$$.@L=1>=A%
3.5 Lexical modeling
Grapheme-based approaches
*$
   ! @7$ =11/ < Q. =11)A @?#$=11)A
H@=110A@ =11:< .=11:A%+
*$<
  *  *     %     
$%
Bootstrapping G2P using MT approaches
3
@=110< =1>1A%24$5
4$5%45*
   $     $ 
%$@7=1>>A%
Use of the Web
@? =110A @ =1>1A  @ =1>:A *    
      $         &  & &*%  
&.  '  $.*      (        $    
+ E * '+E( @ =1>1A   $ 
+E&.%!
6?,,.%!,.
$                         $
   *         *  
&.$% 2$  
,,&.%"
$&.%+@=1>=A?=E+
$$$/&.
>1  ?*E  %            &.  ?=E 
*
%@=1>=*A
*$$&&&*
$,%
3.6 Language modeling
**$,%3
  * $  '* 
(**$,%!**
*.%!.
  **  *        *    %  !       
,%
Word decomposition and use of syntactic information
6$* 
'#(.
* G% ,$   * 
**'33H($%2$
.*
*$$
$$#$'B>1(
,%G*$
'(6@7#=119A!.
@.=1>1<=11/7.=111A@ =11/A2@!"=1>1<#
=11:A7#@3=11)A@.=119A@#=119A?
@F.=11:A%E* G$  # 
*@H=118<.=119A@E=110<
!*=1>=A @ #>000<=110A@*=1>1A'*
*G(% +$**
$        '.$*(        '( 
 *        @  =11/*A% !  
    $*    $
%!
.$$*<
$$  *     *  % !  
$$ $  G@7#=11BA
$6==%
'(
%!*$$
@*  =11/A     @E  =11/  < !*  =1>:A       
2 @G". =119A%!   $  
              *  #%  +  @E  =11)A  
                          
<,,
*%
       '.  
7#. %(# * $  
        $    .      ?%      
                $      %  
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$@7*=111A
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Web or translation-based text data collection
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Word segmentation issues
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                %  !      $      4$ 
5.$*'
$  (% 6  $  $  $ * 
*$$$$
%     . 
**$
%***'%% "
K2" (.@F=11/A%
3.7 Evaluating ASR performance
&'&(,$
$,<$*$
**%G'%%!H(*
*$ $%    #, 
$ * *$% 6   .
 6 $*'($*
#*
*&%6
,*D7'7(
@ =11/AE'E(*'(@2=111AG
 @* =1>1A%!+&
'+&(@=11)< =1>>A.*&@-+!=110A
&&'&&(@-"=11BA%
4. Applications and Tools for U-ASR
4.1 Voice search in three South African languages
$$%
!"$**
  *               @  =1>1A    * 
  *           
%*'($
&**.,
S.@=1>1A%,
*  *    $          $        
*?<$*$
*,*%
.<S$
*&**%
4.2 Interactive Voice Forum for Farmers in Rural India
!"'Avaaj Otalo($=11)""*$-
?3#++G+*%$
 +'$  (
.$%H$$*
$**$%!
"$.,*$;,
'.$$#.$$
$*%(%
$$+G;&*H
'&H(%&H*#
*?""'.*TB1G
+(%6?"$
%&08C,$
*'@E=110A(%2$*$$
@E=1>1A*=:%
4.3 The PI project
!E+"'*6-NAgence Nationale de la Recherche($
H
7*%6$"
'"*N$N*$
"$*=8(%E+"$* 
45'
B%###*E+"(%
4.4 The Rapid Language Adaptation Toolkit (RLAT)
!"E+7'-6=118=11)(!+7
G " 7 *'7(
**$%6!=B
$***
*$
$%!.
*%+
.$'>(*$$**
$'=(
#$*':(
$'8(*'B(
'/(    *    
'9(')(*

.*.@#=119A%!E+7*$
$***
%!$
' +!7G(%**
'>B($$.$.
*%
5. The future of U-ASR
5.1 Endangered languages

%&# =/%
$*T:11$.
'$.0BC(
$.T/B11
$
*.$'45(%&
            $  *        
%+
 '    %(  
#%!
=:DD$$$%$*%D=1>=D1>D>/D$**D 
=8DD%%D$.D*D$DE+7!+3-D 
=B!.'!(DD%.%.%D%
=/45*76DD$$$%%D
*
%6@?=1>1A$
%
5.2 Non written languages
    >  $ $      $ $    
$$%+
*$$G!
*%3$*
$'$
(%+
$$.$'$
  (%          *  *    *  .       
      '        :%(%  +  @  =11/A    @Q.  =110A 
*        $    '  $      (  $  
.$$%!$*
 '  $(   $   '  (% + 
$'$(
$$$*%
$45*
@Q.=110A%@*=1>=AG:E
+G G:        % + @* =1>:A 
    $  G:E $      
%#>80*.$
$,**
#  *$                $     
,%
5.3 Tasks Beyond U-ASR
G   $. *    2!.
*%6*
+@H-..=1>:< .=1>:A%
*%?
@F=1>1AH6@?*#*=1>=A
G!%!*$
%+
*$$
  '*          D        
7    (%  !                  $  $
**$
            '   .         
(%7=1>=$.=9 $       
disconnected languages and styles%
5.4 Organizing the research community on U-ASR
!$.
*$$'(#
#*
&.!'.!(=11)=)
&.!=1>1=0
2!=1>1F"*:1
=9DD$$$%%D=1>=D 
=)DD$$$%%%DD 
=0DD$$$%%%D=1>1D 
:1DD$$$%%"D$D=1>1D>8D)% 
!!U!+7E=11)
!!U!+=1>1
+=1>>:>
&.!=1>=:=
&.EKE!-=1>='6(::
3#:=1>=:8
3          $.        * $.    ! '. 
!($8=1>8:B%
#2!
$!'!(#:/$
$'*&($6
  % ! +  7  '+7(  
!G+:9'!G(*
:%$*
D.*%
#%!*
Processing Under-Resourced Languages %
!'+?(+7%*
 *  "  *  #   - 
-73$
%
6. Conclusion
3      +    
$
%!$$
*<$*
   % 
*#:
# $ * ,     % +
$$'
B($.<$
$*#.
*$%+$
$$
N.%
References
@*  =11/A  -%  *  E%  -  K6%    4        5 
+7E;1/%=)0=0=E*E=11/%
@*=1>1A G"* ?-* G G . G ! $ .
2%G*G+E%+>1+7
E'+7E("7=1>1%B)>B)8%
@F.=11:AG%F.*?
H7E%=11:?$#=11:%=B9=/1%
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Special Issue on Processing Under-Resourced Languages=1>:%
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2H%
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1992. %>%B>9B=1%
@?#=119A 6%?#%% E***.H7%+E%+7E
=119%
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2GG%+E%+7E!.=111%
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7=111%)>))=>%
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,.5E%+G.K=1>1%>0>8>0>9%
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+E*%7*E>000%
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7G77G7=1>1H%B=1>1%:=1:=:%
@ "=11:AF%E% "% %E
E%!+6&..EG*+=11:%0:>11%
@ .=11:A% .2%-4GG?5%Interspeech 2003.
@  =1>1A E%  %  47 G! G   ? 
EH5+!=1>1%>/9.".+=1>1%
@ =1>>A% +% .%#HH*.$
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@ =1>:A  G.+ .FH##%
*%Speech Communication
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%:=::=9%
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Interspeech 2003.
@ .=1>=A+ . HH.GS#%
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@ M>00)A MK% G EG6H*+
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@ $ =11:A % $ 4!     ' (   6 G  
 5% + Proceedings of the 2003 International Workshop Speech and Computer
SPECOM-2003G$=11:%)>B%
@  =110A 2% % K%  % G %+%SL%%*
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L.=11/%
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@ >00BA %  G% F. K%% ?% +   H* G 
% Proc. EurospeechG>00B%>)B>)0%
@  =110A %    E%  F]  %  G  4?           G! 
5+=110%91)9>>% %
@=11:AH+?+7+7!+&*
)77!
'Z1:(?$#%:>>9:>=1*=11:%
@  =110A  V                  H 
WH  % + !  E%
H>9+)-%=110E'(>89>N>8)=%
@=110AF?27E**G G%+!
UE>9'B(08B0BB'=110(
@=110A47G!F
E   5 K  7 ?  2 -%+ =110%
 %=110%
@.R =11BA G% .R G% ER. H% *^ G   6&3
F*E%!F;=11B-+:/B) H7#*
=11B%>81N>89%
@G#=11:A*.!"#6G#&*%G%
E%'+7EZ1:(% =11:++7E
=11:%
@G". =119A E% G". !% 6_ S% !Q.  E%+ 4 G   
N .25 Interspeech’07$
=119%
@G.=1>1A!%G.G% %K%7.% %$.*
%+E%+-!E72=1>1G.K=1>1%>18BN>18)%
@G=1>=A%G?%%F?%2%GF-$.%+
!E=1'>(=1>=%>8==%
@G>00=AL G74
%5+Second International Conference on Spoken Language Processing>00=
@-."=11=A2%-."2%L!%&*4G$!
?*G!573+-?=11=%=%9>/9==!!$%
@-"=11BA2%-"!% $%-$GG.F
3%+E%++7
E+7E=11BE=11B%>1B:>1B/%
@-+!=110A!-+!=110'!10(!GE=110
@3=11)A+% 33% ?*.%K% `.aG  
+E%+&..!!;1)?
+=11)%
@E=1>1A?*EG.#%!$*$!
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@E=1>1A -% E F%7% K E%F !%% E.4"   
+572+%7G=1>1%9::N98=%
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        +% + 72+ ;10 E   =9 
2B>NB8-$L.-L=110%7G%
@E  =11/A  !%  E    %    4+    F        
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'=110(%
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>9'=(=119%:=>::/%
@.=119A!%.G%%GS% *
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   % + Proceedings of the Second International Conference on Language
Resources and Evaluation, %09B0)1=111%
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@=1>1A !  * 3  !" # 4&.     
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@=1>=A!*3!"#4?EG?
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    % Speech Communication Journal, Special Issue on Processing Under-
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=8=0%
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>1%
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7E'E=1>:(!=0:>K=1>:%
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... accessed on 25 December 2022), there are 7151 known living languages in the world (every living language has at least one speaker for whom it is his/her first language). Most of these are low-resource languages, which refers to a language with some (if not all) of the following aspects [1]: a lack of a unique writing system or a stable orthography, a limited presence on the web, a lack of linguistic expertise, and/or a lack of electronic resources for speech and language processing, such as monolingual corpora, bilingual dictionaries, transcribed speech data, pronunciation dictionaries, vocabularies, etc. ...
... The intuitive way to solve this issue is to collect more data. Recently, crowdsourcing has become a popular way to collect a large volume of data at a low cost [1,38]. Despite the clear importance of data collection, in this review paper, we focus on technical approaches to the low-resource language problem and summarize several representative methods, as shown in Table 1. ...
... accessed on 22 December 2022), Multilingual LibriSpeech (MLS) [101], Common Voice [102], etc. For low-resource language speech recognition, early approaches can be found in [1] and recent advances can be found in [103,104]. ...
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With the emergence of deep learning, the performance of automatic speech recognition (ASR) systems has remarkably improved. Especially for resource-rich languages such as English and Chinese, commercial usage has been made feasible in a wide range of applications. However, most languages are low-resource languages, presenting three main difficulties for the development of ASR systems: (1) the scarcity of the data; (2) the uncertainty in the writing and pronunciation; (3) the individuality of each language. Uyghur, Kazakh, and Kyrgyz as examples are all low-resource languages, involving clear geographical variation in their pronunciation, and each language possesses its own unique acoustic properties and phonological rules. On the other hand, they all belong to the Altaic language family of the Altaic branch, so they share many commonalities. This paper presents an overview of speech recognition techniques developed for Uyghur, Kazakh, and Kyrgyz, with the purposes of (1) highlighting the techniques that are specifically effective for each language and generally effective for all of them and (2) discovering the important factors in promoting the speech recognition research of low-resource languages, by a comparative study of the development path of these three neighboring languages.
... Automatic speech recognition (ASR) enables human-computer interaction and improves accessibility by transcribing audio media. However, accurate ASR systems are available in only a fraction of the world's languages because such systems require a vast amount of transcribed speech data [8]. As a result, there has been growing interest in speech processing systems that, instead of using exact transcriptions, can learn from weakly labelled data [9][10][11][12]. ...
... Such a system might be far from perfect. However, when faced with the alternative of having no translation system for an unknown language in an emergency, the imperfect system could be of great use [8]. ...
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This study investigates the use of Visually Grounded Speech (VGS) models for keyword localisation in speech. The study focusses on two main research questions: (1) Is keyword localisation possible with VGS models and (2) Can keyword localisation be done cross-lingually in a real low-resource setting? Four methods for localisation are proposed and evaluated on an English dataset, with the best-performing method achieving an accuracy of 57%. A new dataset containing spoken captions in Yoruba language is also collected and released for cross-lingual keyword localisation. The cross-lingual model obtains a precision of 16% in actual keyword localisation and this performance can be improved by initialising from a model pretrained on English data. The study presents a detailed analysis of the model's success and failure modes and highlights the challenges of using VGS models for keyword localisation in low-resource settings.
... Automatic speech recognition (ASR) is a process of converting speech into a sequence of words by means of algorithms implemented as a software or hardware module. Recent ASR systems exploit mathematical techniques such as Hidden Markov Models (HMM), Artificial Neural Networks (ANN), Bayesian Networks methods, etc. [14]. ...
... Vocals are produced with the vocal cords slightly open. The slightly opened vocal cords vibrate when the air is pumped from the lungs (Berken et al., 2015;Besacier et al., 2014). Furthermore, the air flows out through the oral cavity without getting any resistance. ...
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Language is a sound system. Linguistics sees language as spoken language, spoken language, not written language. However, linguistics does not close itself to written language, because anything related to language is also an object of linguistics. Oral language linguistics is primary, while written language is secondary. In that language, there is no known written language variety, only spoken language variety. Written language can be considered as a "record" of spoken language, as a human effort to "store" the language or to be conveyed to other people who are in a different space and time. However, it turns out that the recorded written language is not perfect. Many elements of spoken language, such as stress, intonation, and tone, cannot be perfectly recorded in written language, whereas in certain languages these three elements are very important. There are several types of script, namely pictographic script, ideographic script, syllabic script, and phonemic script. None of these types of characters can "record" spoken language perfectly. Many elements of spoken language cannot be described by the script accurately and accurately.
... Low resource languages have however received less attention in the development of datasets and machine learning models [18], [19]. Question answer datasets such as TyDiQA [8] have QA sets in more languages than just the high resource ones. ...
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The need for Question Answering datasets in low resource languages is the motivation of this research, leading to the development of Kencorpus Swahili Question Answering Dataset, KenSwQuAD. This dataset is annotated from raw story texts of Swahili low resource language, which is a predominantly spoken in Eastern African and in other parts of the world. Question Answering (QA) datasets are important for machine comprehension of natural language for tasks such as internet search and dialog systems. Machine learning systems need training data such as the gold standard Question Answering set developed in this research. The research engaged annotators to formulate QA pairs from Swahili texts collected by the Kencorpus project, a Kenyan languages corpus. The project annotated 1,445 texts from the total 2,585 texts with at least 5 QA pairs each, resulting into a final dataset of 7,526 QA pairs. A quality assurance set of 12.5% of the annotated texts confirmed that the QA pairs were all correctly annotated. A proof of concept on applying the set to the QA task confirmed that the dataset can be usable for such tasks. KenSwQuAD has also contributed to resourcing of the Swahili language.
... On the other hand, the perceived lack of potential financial benefits from under-resourced languages implies that research regarding them needs to be highly cost-effective. Besacier et al. [5] have reviewed the challenges and research directions for speech processing, focusing on under-resourced languages. Multilingual speech models have been proposed in the literature, which are capable of extracting language-independent features from speech but these models still need to be adapted to a target language with a limited amount of labeled data [6]. ...
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The unavailability of public datasets is the main hurdle for speech processing research targeting under-resourced languages. This paper reports the collection of a speech dataset comprising ten digits from the Kadazan language, which is one of the indigenous southeast Asian languages. Benchmark results for keyword spotting over the dataset using a convolutional neural network, have also been reported, with the benchmark model showing an average classification accuracy of 75.4% across multiple experiments using the dataset. Additionally, the dataset and implementation of the benchmark model have been made public, to facilitate replication and future research in the area of speech processing technologies for the Kadazan language.
... Total languages Indian languages Remarks NIST LRE 03 14 2 Hindi and Tamil NIST LRE 05 7 2 Hindi and Tamil NIST LRE 07 13 4 Bengali, Hindi, Tamil, Urdu NIST LRE 11 24 5 Bengali, Hindi, Punjabi, Tamil, Urdu lack of electronic resources for developing speech applications [119]. A language spoken by a lesser population may not be low-resourced, or a language spoken by millions of speakers can still be low-resourced. ...
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Automatic spoken language identification (LID) is a very important research field in the era of multilingual voice-command-based human-computer interaction (HCI). A front-end LID module helps to improve the performance of many speech-based applications in the multilingual scenario. India is a populous country with diverse cultures and languages. The majority of the Indian population needs to use their respective native languages for verbal interaction with machines. Therefore, the development of efficient Indian spoken language recognition systems is useful for adapting smart technologies in every section of Indian society. The field of Indian LID has started gaining momentum in the last two decades, mainly due to the development of several standard multilingual speech corpora for the Indian languages. Even though significant research progress has already been made in this field, to the best of our knowledge, there are not many attempts to analytically review them collectively. In this work, we have conducted one of the very first attempts to present a comprehensive review of the Indian spoken language recognition research field. In-depth analysis has been presented to emphasize the unique challenges of low-resource and mutual influences for developing LID systems in the Indian contexts. Several essential aspects of the Indian LID research, such as the detailed description of the available speech corpora, the major research contributions, including the earlier attempts based on statistical modeling to the recent approaches based on different neural network architectures, and the future research trends are discussed. This review work will help assess the state of the present Indian LID research by any active researcher or any research enthusiasts from related fields.
... Therefore, it is largely up to scientists and local businesses to develop fundamental and applied research on the Lithuanian language and its modelling. This is valid for almost all under-resourced languages (Besacier et al., 2014). ...
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Intonation is a complex suprasegmental phenomenon essential for speech processing. However, it is still largely understudied, especially in the case of under-resourced languages, such as Lithuanian. The current paper focuses on intonation in Lithuanian, a Baltic pitch-accent language with free stress and tonal variations on accented heavy syllables. Due to historical circumstances, the description and analysis of Lithuanian intonation were carried out within different theoretical frameworks and in several languages, which makes them hardly accessible to the international research community. This paper is the first attempt to gather research on Lithuanian intonation from both the Lithuanian and the Western traditions, the structuralist and generativist points of view, and the linguistic and modelling perspectives. The paper identifies issues in existing research that require special attention and proposes directions for future investigations both in linguistics and modelling.
Chapter
Automatic speech recognition (ASR) has gained wide popularity in last decade. Various devices like mobile phones, computers, vehicles, and audio/video players are now being equipped with ASR technology. The increasing use and dependence on ASR technology leads to research enhancements and opportunities in this domain. This chapter provides a detailed review of various advancements in ASR systems development. It highlights history of speech recognition followed by detailed insight into recent advancements and industry leaders providing latest solutions. ASR framework has been discussed in detail which includes feature extraction techniques, acoustic modeling techniques, and language modeling techniques. The chapter also lists various popular data sets available and discusses generation of new data sets. This work will be helpful for the researchers who are new to this field and are exploring development of new speech recognition techniques.