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Articulatory behaviour during disfluencies in stuttered speech

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The aim of this study is to analyse articulatory movements that occur during Stuttering-Like Dis-fluencies (SLD) and to propose a new classification of SLD based on supraglottic articulatory gestures. 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 production 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 posture , anarchical movements and a combination of above. While the first category only concerns repetitions , the three others can concern SLD categorized as repetitions, prolongations or blocks.
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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-
2991
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
2992
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 ctCt, 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)ct1(i)
2else
Then, a movement at frame t, is detected if the fol-
lowing criterion is validated:
(2)
ctCt
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-
2993
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.
2994
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.
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2995
... For example, Harrington (1987) reported that although the vowel target was not acoustically realized in stuttered consonant-vowel (CV) syllables, anticipatory lingual coarticulation did exist, as evidenced by articulatory data. Furthermore, an articulatory study by Didirková et al. (2019) revealed that stuttering disfluencies perceived as the same type of disfluency (block/prolongation/repetition) are the result of different movement patterns of supralaryngeal articulators. Therefore, a direct examination of articulatory behaviors of stuttering is needed. ...
... Moreover, since EMG typically applies to lip and larynx muscles, how the tongue-the most important articulator-is activated during stuttered speech was not investigated in these studies. Zimmermann (1980b), Didirková et al. (2019), Didirková et al. (2020a), and Didirková et al. (2020b) are the few studies that directly investigated the movements of multiple supralaryngeal articulators during stuttering disfluencies. Zimmermann (1980b) is a cinefluorographic study in which the movements of the tongue tip, tongue dorsum, lower lip, and jaw of PWS during perceptually identified repetitions and prolongations were examined and compared to the articulatory movements in the fluent speech of a PWNS. ...
... Didirková and colleagues used EMA to track the movements of the tongue body, tongue tip, lower and upper lips, and mandible in speech. Didirková et al. (2019) summarized four articulatory patterns based on the movements of all these articulators during disfluencies: reiterations of movements, global maintain of postures, anarchical movements, and a combination of the above. The first articulatory pattern was always related to repetition, whereas the other three were involved in all three types of stuttering disfluencies. ...
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... For example, people who stutter (PWS) experience a range of abnormal physical movements known as concomitant or secondary behaviours. These include upper limb and body movements, facial grimaces, involuntary eye movements, blinks and shortness of breath (Didirkova et al., 2019;Kosmala et al., 2019). However, these secondary behaviours vary considerably across individuals with a study of 85 PWS from Argentina identifying 66 different abnormal movements (Riva-Posse et al., 2008). ...
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Poster
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We intend, via this presentation to present our on-going Multifold Research Program named BeNePhiDiRe (French for “Stuttering : Neurological Imagery, Phonetic Analysis, designed for Diagnosis and Rehabilitation”), which is funded by the French Agence Nationale de la Recherche (ANR) and the French Caisse Nationale de Solidarité pour l’Autonomie (CNSA). The program aims at finding out neurological and phonetic markers for stuttering. Regarding the Neurological fold of our Program, we will focus on tracking the Frontal Aslant Tract and its different or not anatomical aspects according to the different varieties of fluency control (PWS, Persons who had stuttered, Fluent persons) (see Kemerdere et al., 2015 for instance). The phonetic studies follow Didirková’s (2016) works dealing with speech and manual gestures produced by persons who stutter (henceforth PWS). More precisely, we aim at observing articulatory and acoustic specificities by PWS with electromagnetic articulography (EMA) and IRM data. Data obtained in the phonetic studies will be used to carry out an application able to identify stuttering-like disfluencies. The project involves a multidisciplinary team including researchers in linguistics, computer science and neurology on the one hand, and, on the other hand, speech-language therapists specialized in stuttering. First results dealing with speech produced by PWS show that several types of articulatory patterns have been observed during disfluencies. These patterns can be divided in two categories: those which are carried out with slight vertical movements or an immobilization of most articulators, and those produced with movements. Notice that these different patterns are present for blocks, prolongations and repetitions, suggesting that the nomenclature generally used to describe disfluencies does not reflect the articulatory behavior (see Didirková et al.. 2019; 2020). Furthermore, a study arising from our program and presented during this conference (Dodane & Didirková, 2020) reveals atypical manual gestures during stuttering-like disfluencies. References DIDIRKOVÁ I. (2016), Parole, langues et disfluences : une étude linguistique et phonétique du bégaiement. Unpublished PhD thesis, Université Paul-Valéry Montpellier 3, 412 p. DIDIRKOVÁ I., LE MAGUER S., GBEDAHOU D., HIRSCH F. (2019) Articulatory behaviour during disfluencies in stuttered speech. Proceedings of the 19th International Congress of Phonetic Sciences 2019, Melbourne (Australia), 2991-2995. DIDIRKOVÁ I., LE MAGUER S., HIRSCH F. (2020) An articulatory study of differences and similarities between stuttered disfluencies and non-pathological disfluencies. Clinical Linguistics & Phonetics, accepted DODANE C., DIDIRKOVÁ I. (submitted) Speech-gesture relationship during disfluencies in stuttering and non-stuttering French adults. 12th Oxford Dysfluency Conference, Oxford, UK. KEMERDERE, R., DE CHAMPFLEUR, N.M., DEVERDUN, J., COCHEREAU, J., MORITZ-GASSER, S., HERBET, G. & DUFFAU, H. (2016), Role of the Left Frontal Aslant Tract in Stuttering: A Brain Stimulation and Tractographic Study. Journal of Neurology, 263(1):157-167.
Thesis
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Stuttering is a speech fluency disorder. It can be mainly characterized by an increased presence of disfluencies that affect the speech intelligibility. The aim of this thesis is to study stuttering-like disfluencies (SLDs) produced by persons who stutter (PWS) during reading tasks and during spontaneous speech. More specifically, we propose, as our first objective, to verify if any morphological or phonetic elements can explain the presence of these disfluencies. Our second objective is to observe articulatory events before and during SLDs. For the studies dealing with the linguistic and phonetic elements that can be problematic to PWS, 10 French-speaking and 10 Slovak-speaking PWS were recorded while reading a text and while having a conversation in their mother tongue. The studies on speech motor events taking place before and during SLDs were realized by means of an EMA. 4 French-speaking subjects participated in this part of the study (2 PWS and 2 control subjects). Our results show that non-voiced consonants and stops were part of the most problematic elements to produce for PWS. The morphological study reveals that the risk of a SLD appearance was higher when the word contained more morphemes. This result should be correlated to the number of syllables that constitute the word. As for the second couple of studies, they focus on the speech motor events in stuttered speech. Our data show that similar articulatory events can take place in the supraglottic cavity during disfluencies perceived as blocks or prolongations. Furthermore, a disruption of coarticulatory gestures was observed in certain disfluencies.
Article
Full-text available
The purpose of this study was to provide detailed, objective descriptions of stutterers' laryngeal behavior during instances of stuttering within conversational speech. Subjects were 11 adult stutterers who produced stutterings (sound prolongations and sound/syllable repetitions) while their laryngeal behaviors were observed by means of a flexible fiber-optic nasolaryngoscope (fiberscope). Laryngeal behaviors during 86 of the 11 stutterers' stutterings were categorized as adducted, intermediate, or abducted. Results indicate that during sound prolongations the vocal folds were more likely to be adducted and less variable in their movement than during sound/syllable repetitions. Results further indicated that the voicing characteristics of the stuttered sound (voiceless vs. voiced) and the type of stuttering (sound prolongation vs. sound/syllable repetition) interactively influenced laryngeal behavior. It is hypothesized that a complex interaction among the laryngeal, articulatory, and respiratory systems contribute to the occurrence of the inappropriate abductory and/or adductory laryngeal behavior which characterizes prolonged or repeated (stuttered) speech segments.
Chapter
Many physiologically-based models of stuttering that associate laryngeal dysfunction with the disorder (Van Riper, 1971; Adams, 1978; Zimmermann, Smith & Hanley, 1981) share the hypothesis that stutterers have difficulty controlling the rapid initiation and termination of voicing. This hypothesis is supported by behavioral and physiological data drawn from samples of stutterers’ connected speech. Behavioral data show that stutterers demonstrate greater frequency of disfluency and less adaptation when reading aloud passages containing both voiced and voiceless segments than passages containing only voiced segments (Adams and Reis, 1971, 1974; Adams, Riemenschnieder, Metz & Conture, 1975). Physiologic data, obtained from fiberoptic viewing of the vocal folds (Conture, McCall & Brewer, 1977) and the recording of electromyographic (EMG) signals from intrinsic laryngeal muscles (Freeman and Ushijima, 1978; Shapiro, 1980), reveal evidence of abnormal laryngeal activity during stutterers’ disfluent utterances.
Article
We present a new approach to the investigation of dynamic ultrasound tongue imaging (UTI) data, applied here to analyse the subtle aspects of the fluency of people who stutter (PWS). Fluent productions of CV syllables (C = /k/; V = /ɑ, i, ə/) from three PWS and three control speakers (PNS) were analysed for duration and peak velocity relative to articulatory movement towards (onset) and away from (offset) the consonantal closure. The objective was to apply a replicable methodology for kinematic investigation to speech of PWS in order to test Wingate's Fault-Line hypothesis. As was hypothesised, results show comparable onset behaviours for both groups. Regarding offsets, groups differ in peak velocity. Results suggest that PWS do not struggle initiating consonantal closure (onset). In transition from consonantal closure into the vowel, however, groups appear to employ different strategies expressed in increased variation (PNS) versus decreased mean peak velocity (PWS).
Article
Unlabelled: Epidemiological advances in stuttering during the current century are reviewed within the perspectives of past knowledge. The review is organized in six sections: (a) onset, (b) incidence, (c) prevalence, (d) developmental paths, (e) genetics and (f) subtypes. It is concluded that: (1) most of the risk for stuttering onset is over by age 5, earlier than has been previously thought, with a male-to-female ratio near onset smaller than what has been thought, (2) there are indications that the lifespan incidence in the general population may be higher than the 5% commonly cited in past work, (3) the average prevalence over the lifespan may be lower than the commonly held 1%, (4) the effects of race, ethnicity, culture, bilingualism, and socioeconomic status on the incidence/prevalence of stuttering remain uncertain, (5) longitudinal, as well as incidence and prevalence studies support high levels of natural recovery from stuttering, (6) advances in biological genetic research have brought within reach the identification of candidate genes that contribute to stuttering in the population at large, (7) subtype-differentiation has attracted growing interest, with most of the accumulated evidence supporting a distinction between persistent and recovered subtypes. Educational objectives: Readers will be exposed to a summary presentation of the most recent data concerning basic epidemiological factors in stuttering. Most of these factors also pertain to children's risks for experiencing stuttering onset, as well as risks for persistency. The article also aims to increase awareness of the implications of the information to research, and professional preparation that meets the epidemiology of the disorder.
Chapter
The Question: How Is the Discrete Linguistic Representation of an Utterance Related to the Continuously-Varying Speech Signal?One Answer: Quantal Theory and Distinctive FeaturesEnhancement and Overlap: Introducing Variation to the Defining Acoustic CuesConcluding RemarksReferences
Article
It has often been suggested that there is a close relation between problems in the coordination of respiratory, phonatory, and articulatory processes and dysfluencies in speech production. However, empirical support for this hypothesis is scarce, because most studies of speech behavior have been restricted to a single motor process. The present investigation examines the interactions of respiration (specifically the build up of subglottal pressure), phonation, and articulation. Pressure build-up patterns preceding the onset of phonation were studied in 573 fluent utterances of 10 stutterers and in 552 utterances of 7 control subjects. Stutterers evidenced deviant patterns of subglottal pressure build-up much more often than did control speakers. Electroglottographic records of voice onset were classified as either abrupt or gentle and with respect to the presence or absence of gross irregularities in amplitude (shimmer) and period duration (jitter). Stutterers evidenced abrupt voice onsets significantly more often than did controls. The occurrence of jitter and shimmer, however, did not differ significantly across the groups. Acoustic measures of abruptness of voice onset, first syllable duration, and average syllable duration were also obtained, but they failed to differ significantly between the two groups. This study corroborates previous findings that perceptually fluent utterances of stutterers may differ, on a physiological level, from the speech of nonstutterers.
Article
Unlabelled: A deficiency in sensorimotor integration in a person who stutters may be a factor in the pathophysiology of developmental stuttering. To test oral sensorimotor function in adults who stutter, we used a task that requires the coordination of a jaw-opening movement with phonation onset. The task was adapted from previous limb coordination studies, which show that movement coordination depends on intact proprioception. We hypothesized that adult stutterers would show deficient jaw-phonatory coordination relative to control participants. The task required initiation of phonation as a jaw-opening movement passed through a narrow spatial target. Target amplitude and jaw movement speed were varied. The stuttering group showed significantly higher movement error and spatial variability in jaw-phonatory coordination compared to the control group, but group differences in movement velocity or duration were not found. The aberrant jaw-phonatory coordination of the stuttering participants suggests that stuttering is associated with an oral proprioceptive limitation, although, the findings are also consistent with a motor control deficit. Learning outcomes: As a result of this activity, reader will (1) learn about a hypothesis and evidence supporting the view that a sensorimotor deficit contributes to chronic developmental stuttering and (2) will obtain information about the role of proprioception in multi-articulatory coordination and how it can be tested using an oral-phonatory coordination task.
PERCEVAL: a Computer-Driven System for Experimentation on Auditory and Visual Perception
  • C André
  • A Ghio
  • C Cavé
  • B Teston
André, C., Ghio, A., Cavé, C., Teston, B. 2003. PERCEVAL: a Computer-Driven System for Experimentation on Auditory and Visual Perception. International Congress of Phonetic Sciences (ICPhS) Barcelona, Spain. UAB 1421-1424.