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ARTICULATORY BEHAVIOUR DURING DISFLUENCIES IN
STUTTERED SPEECH
Ivana Didirková1,2, Sébastien Le Maguer3, Fabrice Hirsch4, Dodji Gbedahou4
1EA 1569 TransCrit, Université Paris 8, France,
2CNRS & UMR 7018 Laboratoire de phonétique et phonologie, Université Paris 3, France
3ADAPT Centre, Sigmedia Lab, EE Engineering, Trinity College Dublin, Dublin, Ireland
4CNRS & UMR 5267 Praxiling, Université Paul-Valéry Montpellier 3, France
ivana.didirkova@univ-paris8.fr, lemagues@tcd.ie, fabrice.hirsch@univ-montp3.fr, hubertgbedahou@yahoo.fr
ABSTRACT
The aim of this study is to analyse articulatory
movements that occur during Stuttering-Like Dis-
fluencies (SLD) and to propose a new classifica-
tion of SLD based on supraglottic articulatory ges-
tures. To carry out this study, ElectroMagnetic Ar-
ticulography (EMA) data were collected within two
Persons Who Stutter (PWS) reading two texts. All
pathological disfluencies were identified in the pro-
duction of PWS categorized as blocks, repetitions
and prolongations. Results show four articulatory
patterns occurring during the SLD: Reiterations of
series of movements leading to sound(s) or syllable
repetitions, global maintain of the articulatory pos-
ture, anarchical movements and a combination of
above. While the first category only concerns repeti-
tions, the three others can concern SLD categorized
as repetitions, prolongations or blocks.
Keywords: stuttering; stuttering-like disfluencies;
speech production; articulatory description.
1. INTRODUCTION
1.1. Stuttering
Stuttering can be defined as an alteration of speech
fluency having negative implications on communic-
ation ([7]). More precisely, this disorder is con-
sidered as a motor trouble that momentarily stops
speech flow. Several types of stuttering are men-
tioned in literature: developmental stuttering start-
ing between age 3 and 7 and disappearing spontan-
eously, persistent stuttering beginning at the same
period but remaining present in adolescence and
adulthood; as well as acquired stuttering, gener-
ally due to a neurological accident ([7]). Accord-
ing to [15], 5% of the worldwide population have
been concerned by this disorder but its prevalence
is at 1% since the rate of ‘spontaneous’ remissions
in children is evaluated at 80%. If the origins of
stuttering remain a challenge for researchers, recent
works allow formulating several hypotheses about
the aetiology of developmental and persistent stut-
tering. Indeed, the origins of this trouble should be
multi-factorial since different studies point out ge-
netic and neurological specificities in Persons Who
Stutter (PWS).
1.2. Phonetics of stuttering
As mentioned above, stuttered speech is charac-
terized by the presence of disfluencies that are
more frequent than in non-stuttered speech. These
Stuttering-Like Disfluencies (SLD) can be classi-
fied mainly as blocks, prolongations and repetitions
(e.g. [11]) but other types of speech flow alterations
can be found in PWS (see [3] for a literature review).
Moreover, SLD present several specificities com-
pared to non-pathological disfluencies. For ex-
ample, stuttering is one of the scarce disorders where
disfluencies can frequently split a syllable ([17]).
In another study, [4] show that alterations of
speech flow by PWS are generally accompanied by
audible tensions. The same research shows that con-
sonants can be prolonged in stuttering-like disfluen-
cies, while this is not the case in normal alterations
of speech flow in French. Finally, they observe that
the duration of SLD is generally more important and
more variable.
1.3. Physiological description of SLD
However, classification of speech disfluencies as
non-pathological or pathological is not an easy task
given that several types of disfluencies are present
both in non-stuttered and stuttered speech. For in-
stance, sound prolongations, repetitions, as well as
silences, can also be observed in people who do not
stutter. This is the reason why physiological descrip-
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tions are necessary to determine what distinguish
stuttering-like disfluencies and non pathological dis-
fluencies.
Concerning the respiratory level, [13] observe that
the respiratory movements during pre-phonatory
phases are different in PWS. Other studies dealing
with this topic have been carried out (e.g. [10], [18]).
The laryngeal level also presents some specificities.
Indeed, [2] observe an abnormal activity of the vo-
cal folds during stuttering-like disfluencies. There-
fore, [8] prefer to talk about myoclonic movements
(spasms) to describe the glottis functioning in PWS.
Curiously, The literature concerning the supra-
glottic level in subjects who stutter remains scarse
and often deal with fluent speech produced by
PWS [5]. Among studies dealing with SLD, [6] re-
veal a deficiency in the jaw-phonatory connection.
The speech motor behaviour in PWS would tend
to be less efficient or even immature in the man-
agement of the coordination of different articulat-
ors. Thus, [14] supposes alterations of speech flow
are due to a coarticulation disruption. More pre-
cisely, [14] estimates that, in a sequence, trans-
ition between the two sounds should be the con-
sequence of a disrupted antagonist muscles activ-
ity. This fault line would correspond to the moment
where stuttering-like disfluencies emerge.
1.4. Objective and hypothesis
As mentioned above, few studies have been carried
out on the way disfluencies are produced. Further-
more, most of these studies are based on extrapola-
tions made from acoustic data. However, while it is
possible to obtain many informations thanks to the
acoustic signal, EMA data allow a more direct ob-
servation.
Consequently, the aim of this study is to provide
a description of articulatory behaviour during SLD.
More precisely, our objective is to analyse articulat-
ory movements that occur during SLD and to pro-
pose a classification based on supraglottic articu-
latory gestures. Our hypothesis is that the nomen-
clature generally used to describe disfluencies does
not reflect the articulatory behaviour. If a same per-
cept can be a result of different articulatory gestures
([12]), depending on speaker, phonetic environment,
etc., we postulate that the same articulatory patterns
could be at the origin of several perceptual types of
disfluencies ([3]).
2. METHODS
2.1. Data acquisition & participants
EMA data were collected by means of an electro-
magnetic articulograph Carstens AG501 3D at the
Lorraine Research Laboratory in Computer Science
and its Applications (LORIA, Nancy, France) with
a sampling rate of 250 Hz and an accuracy of 0.3
mm. All data were stocked in a .pos file and syn-
chronized with a sound recording (44.1 kHz, 16 bits,
.wav). 10 sensors (2x3 mm) per subject were used:
two were fixed on the lips of each subject (1 in
the middle of the upper lip and another one in the
middle of the lower lip). 3 coils were situated on the
tongue of each subject; one on the tongue tip, one
on the tongue body and one on the tongue back. To
track the mandible’s movements, another sensor was
placed on the subjects’ jaw. The palate’s form was
indicated by means of a seventh coil. Other sensors
were used to control head’s movements.
Two PWS, one female and one male, aged re-
spectively 23 and 26, both native speakers of French
and Wolof, were recruited for this study. Participants
were recorded while reading the text of an Alphonse
Daudet’s novel, La chèvre de Monsieur Seguin (Mis-
ter Seguin’s goat), in French and an Aesop’s fable,
Le lion et le rat (The lion and the rat). These record-
ings took place in a soundproof room.
2.2. Data analysis
2.2.1. Acoustic and perceptual analysis
Data analysis rely on perceptual and acoustic iden-
tification of stuttering-like disfluencies. First, three
persons (two of the authors and a speech therapist
specialized in stuttering) identified all SLD in the
production of PWS, based on perception and on the
speech signal, without classifying these disfluencies.
They then discussed cases where they did not reach
agreement. In order to confirm their annotations and
identify the perceptual class of every disfluency, a
perception test has been carried out within the free-
ware Perceval ([1]), based on .wav files extracted for
each SLD. Five naïve listeners were then asked to
categorize SLD as blocks, repetitions, prolongations
or combined disfluencies (Fleiss’ kappa: 0.752).
Authors discussed cases where naïve listeners did
not reach agreement. Speech alterations identified
as combined disfluencies were eliminated from fur-
ther study. Moreover, repetitions of diphones, syl-
lables, words and other sequences containing more
than one phone were excluded from our research in
order to minimize influence of coarticulation on our
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observations.
After exclusion of combined disfluencies and dis-
fluencies concerning more than one phone, 250 SLD
were obtained. Their distribution according to the
perceptual type of disfluency and according to the
subject can be found in the Table 1. Although both
subjects have a severe stuttering, the distribution of
disfluencies is not the same: whereas speaker F pro-
duces 89 disfluencies, mostly blocks and prolonga-
tions, 161 of disfluencies analysed in this paper were
produced by M. For the speaker M, repetitions are
the most present perceptual disfluency type. Due
to these idiosyncratic characteristics of SLD in our
speakers, only 55 disfluencies (22%) were blocks.
Other 39.2% of disfluencies were prolongations. Re-
petitions represented 38.8% of all analysed SLD. All
of SLD were spontaneous, e.g. no factors were ma-
nipulated to elicit these disfluencies.
Table 1: Distribution of stuttering-like disfluen-
cies according to their perceptual type and accord-
ing to the speaker
Repet. Prolong. Block Total
Female 17 34 38 89
Male 80 64 17 161
Total 97 98 55 250
2.2.2. Automatic articulatory analysis
We can assess if there was a movement during the
production by inspecting the articulatory dynamics.
To do so, we have defined the following methodo-
logy. First, we consider t∈[0..T]the index of the
frame and Ctthe set of coils at frame t. From each
coil ct∈Ct, we compute the local velocity based
the central finite difference as defined in [16] using
Equation (1).
(1) ∆(ct) =
0t=0
0t=T
r∑
i∈{x,y,z}
ct+1(i)−ct−1(i)
2else
Then, a movement at frame t, is detected if the fol-
lowing criterion is validated:
(2) ∑
ct∈Ct
f(∆(ct),θc)>|Ct|/2
with f(v,θ) = 1 if vis beyond θand 0 else.
In this study, we define θcat 30% of the aver-
age dynamic of the whole corpus for each coil c.
This large threshold allows us to be less sensitive
to a movement and therefore enhance non-activity
detection. Finally, we focus our analysis to the seg-
ments annotated as a disfluent production. For each
segment, we ignore the 10% first and the 10% last
frames in order to avoid transition effect. From
the remaining ones, we compute the percentage of
frames considered in movement.
2.2.3. Manual articulatory analysis
After this classification, the Visartico software ([9])
was used to visualize and analyse the vertical move-
ments (the z axis) of the upper and lower lip, the
tongue tip, the tongue body, the tongue back and
the mandible in segments that included the stuttered
phone and its preceding and subsequent phones.
3. RESULTS
3.1. Percentage of frames in movement by type of
SLD
As we can see in Table 2, even though a threshold
has been defined to capture a maximum of non-
movement frames, there are still around 40% of
them considered as moving in average. Further-
more, the standard deviation shows an important
variability across the segments. Some segments are
even reaching 80% of movement.
Table 2: Average movement percentage per type
and per disfluency type. The standard deviation is
indicated in parenthesis.
Female Male
Repetition 46.28 (13.15) 48.05 (12.91)
Prolong. 31.18 (13.43) 40.80 (9.60)
Block 42.26 (11.69) 47.18 (11.08)
If we observe what happens for each type of
SLD, it is possible to notice, in average, that repeti-
tions are the disfluencies produced with the greatest
amount of frames in movement in speakers F (aver-
age: 46.28%, SD: 13.15%) and M (average: 48.05,
SD: 12.91%). Blocks constitute the second type
of SLD where frames in movement are the most
present in F (average: 42.26%, SD: 11.69%) and
M (average: 47.18%, SD: 11.08%). Finally, less
frames are in movement in prolongations (average:
31.18%, SD: 13.43 in F; average: 40.8%, SD: 9.6 in
M).
3.2. SLD and articulatory patterns
Four main categories of disfluencies have been re-
vealed by EMA data (a chi-squared goodness-of-
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fit test: χ2=187.28, df=3, p=.000): a) Reiterations
of series of movements leading to sound repeti-
tions (rep); b) Combination of a global maintain of
an articulatory posture and articulatory movements
(comb); c) Global maintain of the articulatory pos-
ture with or without an acoustic output and with or
without anticipation of the subsequent phone (no–
mov); d) Presence of articulatory movements with
or without inter-articulatory coupling (mov).
As shown in Figure 1, while the first category
mostly concerns repetitions, the three others can
concern SLD categorized as repetitions, prolonga-
tions or blocks, showing that a same articulatory
pattern can be observed for the 3 types of disfluen-
cies (chi-squared test for independence: χ2=39.302,
df=6, p=.000, effect size: 0.560).
Figure 1: Proportions of disfluency types. The
area of each rectangle gives the proportion of the
perceptual type (width) and the articulatory pat-
tern (height).
block prolongation repetition
Perceptual type of disfluency
Art. pattern comb movno-movrep
3.3. Duration and SLD type
A linear model was fit with articulatory pattern and
perceived disfluency as the independent variables
and length as the dependent variable. The model
was significant: F=11.68 on 5 and 244 df, p=.000.
Our data indicate a clear preference of the combined
articulatory pattern to occur within the longest dis-
fluencies. The duration decreases when the disflu-
ency is characterized by the presence of a movement
during whole disfluency. The shortest disfluencies
are those where we observe a global maintain of ar-
ticulatory posture and a repetition of an articulatory
movement. These effects are mostly prominent in
blocks as shown in Figure 2.
4. DISCUSSION AND CONCLUSION
To sum up, most of SLD are carried out with frames
in movement. If movements are generally observed,
it is possible to note that their ‘efficiency’ is vari-
able: indeed, if some of them are audible during
prolongations and repetitions for instance, others are
ineffective since they are inaudible, as in blocks. It
Figure 2: Types of disfluencies and their length.
0
2
4
6
block prolongation repetition
Perceptual type of disfluency
Disfl. length in s
Art. pattern comb movno-movrep
is important to highlight that movements’ efficiency
during SLD can be due a) to the degree of constric-
tion between the different articulators and b) to the
respiratory and/or the laryngeal level. Indeed, if air
pressure and/or vocal folds configuration are not ad-
apted, the acoustic output will be absent.
Moreover, several types of articulatory patterns
have been observed during disfluencies. These pat-
terns can be divided in two categories: those which
are carried out with slight vertical movements or an
immobilization of most articulators, and those pro-
duced with movements. Among the last category
cited, there are SLD presenting inter-articulators
coupling and SLD where articulators move inde-
pendently of each other. These different patterns are
present for blocks, prolongations and repetitions. In
other terms, it means that a same type of disfluencies
can be produced in different ways. This allows to
draw a parallel between disfluencies and the Quan-
tal theory [12]; This theory supposes that a same per-
cept can be the results of several different articulat-
ors’ positions. As for disfluencies, a same disfluency
can be the result of different configurations.
Concerning articulatory patterns, it has been
shown that the longest disfluencies are carried out
with a combination of several articulatory configur-
ations. This result suggests that more there are dif-
ferent articulatory patterns during a disfluency and
longer the disfluency will be. Consequently, making
an effort seems to be ineffective in PWS when they
have to overcome a disfluency.
Our study reports articulatory patterns seen in
their totality (all articulators taken together). Thus,
it seems necessary to investigate the contribution
of each articulator to observed patterns. Our res-
ult should finally be compared to an articulatory de-
scription of disfluencies of non-stuttering speakers.
Finally, we think that this research should be car-
ried out in a longitudinal approach in order to verify
how articulatory patterns progress during a speech
therapy, showing that articulatory data should be
used more frequently during a stuttering reeducation
to note patient’s evolution.
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5. ACKNOWLEDGMENT
This research was partly supported by « MoSpeeDi.
Motor Speech Disorders : characterizing phon-
etic speech planning and motor speech program-
ming/execution and their impairments », subside
CRSII5_173711/1Sinergia du Fond National Suisse
de la Recherche Scientifique
This research was partly supported by the French
Agence Nationale de la Recherche and by the
Caisse nationale de solidarité pour l’autonomie un-
der Grant No. ANR-18-CE36-0008 (Project BE-
NEPHIDIRE, PI: Fabrice Hirsch).
This research was also partly supported by the
Irish Research Council (IRC) and by the ADAPT
Centre. The ADAPT Centre for Digital Con-
tent Technology is funded under the SFI Research
Centres Programme (Grant 13/RC/2106) and isco-
funded under the European Regional Development
Fund.
6. REFERENCES
[1] André, C., Ghio, A., Cavé, C., Teston, B. 2003.
PERCEVAL: a Computer-Driven System for Ex-
perimentation on Auditory and Visual Percep-
tion. International Congress of Phonetic Sciences
(ICPhS) Barcelona, Spain. UAB 1421–1424.
[2] Conture, E. G., Schwartz, H. D., Brewer, D. W.
1985. Laryngeal behavior during stuttering: A fur-
ther study. Journal of Speech, Language, and Hear-
ing Research 28(2), 233–240.
[3] Didirkova, I. 2016. Parole, langues et disflu-
ences: une étude linguistique et phonétique du
bégaiement. PhD thesis Université Paul Valéry-
Montpellier III.
[4] Didirkova, I., Fauth, C., Hirsch, F., Luxardo, G.,
Diwersy, S. 2016. Disfluences normales vs. disflu-
ences sévères: une étude acoustique. JEP-Journées
d’Etudes sur la Parole volume 1 191–199.
[5] Heyde, C. J., Scobbie, J. M., Lickley, R., Drake,
E. K. 2016. How fluent is the fluent speech of
people who stutter? a new approach to measuring
kinematics with ultrasound. Clinical linguistics &
phonetics 30(3-5), 292–312.
[6] Loucks, T. M., Luc, F., Sasisekaran, J. 2007. Jaw-
phonatory coordination in chronic developmental
stuttering. Journal of Communication Disorders
40(3), 257–272.
[7] Monfrais-Pfauwadel, M.-C. 2014. Bégaiement, bé-
gaiements. Un manuel clinique et thérapeutique.
De Boeck-Solal.
[8] Monfrais-Pfauwadel, M.-C., Tromelin, O., Mou-
gin, A.-L., Ormezzano, Y. 2005. Utilisa-
tion des explorations multimédia synchrones dans
l’objectivation des événements laryngés lors des
bégayages. Revue de laryngologie, d’otologie et de
rhinologie 126(5), 341–345.
[9] Ouni, S., Mangeonjean, L., Steiner, I. Sept. 2012.
VisArtico: a visualization tool for articulatory
data. 13th Annual Conference of the International
Speech Communication Association - InterSpeech
2012 Portland, OR, United States.
[10] Peters, H. F., Boves, L. 1988. Coordination of aero-
dynamic and phonatory processes in fluent speech
utterances of stutterers. Journal of Speech, Lan-
guage, and Hearing Research 31(3), 352–361.
[11] Piérart, B. 2011. Les bégaiements de l’adulte
volume 5. Editions Mardaga.
[12] Stevens, K. N., Hanson, H. M. 2012. Chapter 12:
Articulatory–acoustic relations as the basis of dis-
tinctive contrasts. The Handbook of Phonetic Sci-
ences 116, 424.
[13] Watson, B. C., Alfonso, P. J. 1987. Coordination of
prephonatory events in mild and severe stutterers.
In: Speech Motor Dynamics in Stuttering. Springer
197–207.
[14] Wingate, M. E. 2012. The structure of stuttering:
A psycholinguistic analysis. Springer Science &
Business Media.
[15] Yairi, E., Ambrose, N. 2013. Epidemiology of stut-
tering: 21st century advances. Journal of fluency
disorders 38(2), 66–87.
[16] Young, S., Evermann, G., Gales, M., Hain, T., Ker-
shaw, D., Liu, X., Moore, G., Odell, J., Ollason, D.,
Povey, D., others, 2006. The HTK book (v3. 4).
[17] Zellner, B. 1992. Le bé bégayage et euh...
l’hésitation en français spontané. JEP volume 19
481–487.
[18] Zocchi, L., Estenne, M., Johnston, S., Del Ferro,
L., E. Ward, M., T. Macklem, P. 07 1990. Respirat-
ory muscle incoordination in stuttering speech. The
American review of respiratory disease 141, 1510–
5.
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