Coarticulatory Resistance Research Articles

Speakers coarticulate less in response to both real and imagined communicative challenges: An acoustic analysis of the LUCID corpus

Overlap of adjacent articulatory gestures leads to coarticulation. Understanding how hyperarticulated intelligibility-enhancing clear speech modifications affect coarticulation can inform theories of phonetic variation and speech intelligibility. However, prior research yielded mixed findings regarding the relationship between hyperarticulation and coarticulatory patterns. This study extends previous work by analyzing the degree of coarticulation across several different communicative conditions in the LUCID corpus (Baker & Hazan, 2010). Southern British English speakers completed an interactive spot-the-difference task with a partner with and without a communicative barrier (e.g., speech degraded by talker babble). They also read sentences without an interlocutor casually and clearly. Diphones in keywords produced in both tasks were analyzed using two whole-spectrum measures, with greater spectral distance and shorter coarticulatory overlap between the diphones indexing less coarticulation. Results revealed that speakers coarticulated less in response to both real (interactive task) and imaginary (sentence-reading) communicative challenges. Speakers furthermore varied the degree of coarticulatory resistance in different real communicative barriers. Diphones with greater consonant articulatory constraint were less sensitive to differences between the conditions, suggesting a limit to the hyperarticulation-induced phonetic variation. The findings agree with the models of targeted speaker adaptations assuming coarticulatory resistance in hyperarticulated clear speech (the H&H theory: Lindblom, 1990).

Lithuanian and Latvian laterals: Comparison of acoustic properties

The aim of the paper is to examine how acoustic contrast manifests itself between /l/ and /ʎ/ in Latvian, as well as /l/ and /lʲ/ in Lithuanian. For the study, speech recordings of 6 adult informants (3 Lithuanian and 3 Latvian male speakers) have been analysed. Initial and final laterals in closed symmetric [l]V[l] sequences and intervocalic syllable-initial laterals in V[l]V sequences have been examined. During the analysis, the focus is placed mainly on locus equations, as well as changes in formant structure (especially F1 and F2) triggered by position and vocalic context. Acoustic data demonstrates differences in coarticulation effects between Latvian palatal /ʎ/ and Lithuanian palatalized /lʲ/. The formant structure of /ʎ/ and /lʲ/, unlike the corresponding non-palatal laterals, is more stable and less dependent on the quality of adjacent vowels. Vowel context affects the degree of palatalization, e. g. palatalized [lʲ] next to [ɪ], [iː] and [eː] is pronounced “softer” than next to [ɔ̟], [o̟ː], [ʊ̟], and [u̟ː]. Latvian /ʎ/ is characterized by a more stable vowel F2 locus, which indicates higher degree of coarticulatory resistance to vowel effects; the quality of /lʲ/, on the contrary, depends more on vowel context. The same is true (although to lesser degree) for the Lithuanian /l/. The assumption about the similarity of Latvian non-palatal /l/ and Lithuanian palatalized /lʲ/ is only partly supported by the recent data. In terms of the degree of coarticulation (indicated by slope values of locus equations), Latvian /l/ is closer to Lithuanian /lʲ/, while its formant structure, especially low F2, brings it closer to Lithuanian /l/.

Coarticulation is reduced in clear speech produced with protective face masks

Talkers dynamically modify their coarticulatory patterns when producing listener-oriented hyperarticulated clear speeches. This study examined how the use of protective face masks interacts with the production of intelligibility-enhancing clear speech to impact coarticulation. A native and a non-native speaker of English read sentences in a clear and conversational speaking style with and without a surgical mask. Coarticulation between word-internal adjacent segments was analyzed with a whole-spectrum analysis including spectral distance and segment overlap duration. Both speakers coarticulated less in clear than in conversational speaking style as indicated by the larger spectral distance and shorter overlap duration between adjacent segments. Coarticulation was further reduced when clear speech was produced with a mask by the native speaker but not by the non-native speaker. The findings showed that producing hyperarticulated intelligibility-enhancing clear speech also involves reducing coarticulatory overlap across adjacent segments. Coarticulatory resistance was adaptively reinforced in the presence of the additional communicative barrier, face mask, particularly for the speaker with extensive experience with the target language. Such cumulative reduction of coarticulation may in part underlie the larger perception-in-noise benefit for clear speech produced with a mask for the native compared to the non-native talker.

A Cross-Sectional Age Group Study of Coarticulatory Resistance: The Case of Late-Acquired Voiceless Fricatives in English.

As a class, fricatives are more "resistant" to consonant-vowel coarticulation than other English sounds. This study investigates the relative coarticulatory resistance of /θ, s, ʃ/ in child and adult speech to better understand the acquisition of individuated speech sounds. Ten 5-year-old children, seven 8-year-old children, and nine college-age adults produced [əFV] sequences in carrier phrases, where F was /θ/, /s/, or /ʃ/ and V was /æ/, /i/, or /u/. In Experiment 1, coarticulation was perceptually indexed: 65 adults predicted the target stressed vowel based on forward-gated audiovisual speech samples for a subset of four speakers from each age group. In Experiment 2, dynamic spectral measures of the /əFV/ sequences were analyzed using smoothing spline analysis of variance to again test for vowel effects on fricative articulation across age groups. The perceptual results indicated that fricatives blocked vowel-vowel coarticulation across speaker age groups. Contrary to expectation, vowels were most accurately predicted when F was /s/ and not when it was /ʃ/ or /θ/ across age groups. Acoustic results indicated the expected biomechanically motivated /ʃ/ > /s/ > /θ/ coarticulatory resistance hierarchy in adults' speech. By contrast, /ʃ/ > /s/ were similarly influenced by context in 8-year-olds' speech, and the results from 5-year-olds' speech suggested an influence of order of acquisition in that /θ/ was surprisingly resistant to coarticulation. The study results are taken to suggest that a temporal constraint on fricative articulation interacts with biomechanical constraints during development to influence patterns of coarticulation in school-age children's speech.

The colour of liquid: a sociophonetic analysis of the changing positional allophony of the South African English lateral approximant

This article provides a sociophonetic analysis of General South African English /l/, based on the naturalistic speech of 50 male and female L1-speakers of this variety of South African English (SAfE), all from Cape Town and ranging from 18-82 years of age. Emphasis falls on testing descriptions provided by the impressionistic literature of the so-called ‘colour’ of the two main allophones of this phoneme i.e. those in initial and final positions; and on determining whether there has been any change in this regard. The relevant phonetic (acoustic) analysis focuses on the parameters of F2 or F2-F1 (as general measures of ‘colour’) and co-articulatory resistance (as an additional parameter of darkening, particularly with respect to final-/l/) to determine the overall status of /l/ as well as to determine whether or not the acoustic difference between initial-/l/ and final-/l/ meets the criteria provided by Recasens (2012) for extrinsic allophony. These parameters also constitute dependent variables for a statistical analysis which determines the relative effect of one internal (positional allophony) and two external (age and gender) independent variables on these parameters. The results provide evidence to suggest that pronouncements in the impressionistic literature are incorrect. While there has been a darkening of /l/-colour in apparent time, /l/-colour in General SAfE has been and is consistently of a relatively dark kind, as in the case of the Australasian varieties of English, the closest relatives of SAfE. Furthermore, results show that any remaining difference in colour between the two positional allophones is purely the result of intrinsic allophony i.e. General SAfE does not display a full RP-like clear-dark allophony. Results do, however, confirm that female speakers have a slightly more fronted variant of initial-/l/, probably a prestige variant. Keywords: South African English, English phonetics, English accents, sociophonetics, acoustic analysis, liquids, alveolar lateral, sound change

Alveolar stops exhibit greater coarticulatory resistance than retroflexes and dentals in Malayalam

Tight coronal contrasts in Malayalam geminates (V1t̪:V2 vs. V1t:V2 vs. V1t:V2) are examined in an Ultrasound study of tongue contours to understand the nature of coarticulatory resistance and aggressiveness. Degree of Articulatory Constraint (DAC) predicts that articulatory complexity mitigates the nature of coarticulatory resistance (CR) cross-linguistically. Findings from our study of Ultrasound tongue contours are contrary to the predictions of the DAC, where the expectation is that the directionality of CR and aggressiveness will be Vt̪:V < Vt:V < Vt:V. We find that the order of CR is Vt:V < Vt̪:V < Vt:V. Greater variability in tongue constriction location in retroflex and dentals is found compared to alveolars. Low neighborhood density alveolars exhibit low contextual adjustments even at the constriction. This is a consequence of greater articulatory complexity. Malayalam alveolars are distributionally restrictive compared to dental and retroflex places of articulation. Alveolars in Malayalam have low neighborhood densities which may indeed govern coarticulatory resistance and aggressiveness of this place of articulation. These findings have been corroborated in an acoustic study of Malayalam stops (Dutta et al., 2019). We discuss the implications of our findings for DAC and propose that sparse lexical representation coerces coarticulatory resistance in tight coronal place contrasts.

Prosodic structurally conditioned variation of coarticulatory vowel nasalization in Mandarin Chinese: Its language specificity and cross-linguistic generalizability.

This study compares prosodic structural effects on nasal (N) duration and coarticulatory vowel (V) nasalization in NV (Nasal-Vowel) and CVN (Consonant-Vowel-Nasal) sequences in Mandarin Chinese with those found in English and Korean. Focus-induced prominence effects show cross-linguistically applicable coarticulatory resistance that enhances the vowel's phonological features. Boundary effects on the initial NV reduced N's nasality without having a robust effect on V-nasalization, whose direction is comparable to that in English and Korean. Boundary effects on the final CVN showed language specificity of V-nasalization, which could be partly attributable to the ongoing sound change of coda nasal lenition in Mandarin.

Vocalic activation width decreases across childhood: Evidence from carryover coarticulation

This study is the first to use kinematic data to assess lingual carryover coarticulation in children. We investigated whether the developmental decrease previously attested in anticipatory coarticulation, as well as the relation between coarticulatory degree and the consonantal context, also characterize carryover coarticulation. Sixty-two children and 13 adults, all native speakers of German, were recruited according to five age cohorts: three-year-olds, four-year-olds, five-year-olds, seven-year-olds, and adults. Tongue movements during the production of ə.CV.Cə utterances (C = /b, d, g/, V = /i, y, e, a, o, u/) were recorded with ultrasound. We measured vowel-induced horizontal displacement of the tongue dorsum within the last syllable and compared the resulting coarticulatory patterns between age cohorts and consonantal contexts. Results indicate that the degree of vocalic carryover coarticulation decreases with age. Vocalic prominence within an utterance as well as its change across childhood depended on the postvocalic consonant’s articulatory demands for the tongue dorsum (i.e., its coarticulatory resistance): Low resistant /b/ and /g/ allowed for more vocalic perseveration and a continuous decrease, while the highly resistant /d/ displayed lower coarticulation degrees and discontinuous effects. These findings parallel those in anticipation suggesting a similar organization of anticipatory and carryover coarticulation. Implications for theories of speech production are discussed.

Lowered F2 observed in uvular rhotics involves a tongue root gesture: Evidence from Upper Sorbian.

Upper Sorbian, an endangered West Slavic language spoken in Germany, is unusual among Slavic languages in having a uvular rhotic /ʀ/. This paper focuses on the gestural configuration and coarticulatory resistance of the uvular rhotic and explores the relation between the articulation and acoustics of this sound. Ultrasound tongue imaging data were collected from six native speakers of Upper Sorbian, who produced /ʀ/ in word-initial, intervocalic, and word-final positions next to the vowels /e a o/. Smoothing Spline ANOVAs were used to compare tongue contours within and across phonetic contexts. Differences in the tongue root and tongue body position were also calculated across environments and compared using a measure of coarticulatory resistance. The results revealed that the sound was produced with considerable tongue root retraction and a uvular-pharyngeal tongue body constriction. The tongue root had a high resistance to coarticulatory effects, while the tongue body did not. The results suggest that the tongue root retraction into the pharyngeal cavity results in observed high F1 and low F2 effects associated with unpalatalized rhotic consonants and may explain perceptual similarity between uvular and alveolar rhotics. Articulatory constraints on the tongue root also account for phonotactic distribution of the rhotics across languages.

Articulatory characterization of English liquid-final rimes

Articulation of liquid consonants in onsets and codas by four speakers of General American English was examined using real-time MRI. Midsagittal tongue posture was compared for laterals and rhotics produced in each syllable margin, adjacent to 13 different vowels and diphthongs. Vowel articulation was examined in words without liquids, before each liquid, and after each liquid, to assess the coarticulatory influence of each segment on the others. Overall, nuclear vocalic postures were more influenced by coda rhotics than onset rhotics or laterals in either syllable margin. Laterals exhibited greater temporal and spatial independence between coronal and dorsal gestures. Rhotics were produced with a variety of speaker-specific postures, but were united by a greater degree of coarticulatory resistance to vowel context, patterns consistent with greater coarticulatory influence on adjacent vowels, and less allophonic variation across syllable positions than laterals.

Coarticulatory resistance in Assamese stops

The nature and extent of coarticulation and coarticulatory resistance of speech segments have been found to be dependent on the size, shape, and density of contrasts, in addition to neighborhood densities of segment sequences. While high density of contrasts leads to high coarticulatory resistance, low density of contrasts leads to low coarticulatory resistance. Assamese, an Indo-Aryan (IA) language, unlike the other IA languages which exhibit a two-way coronal place contrast, contains only an alveolar stop. Due to the relative low density of the alveolar, we hypothesize that the Assamese alveolar stops will exhibit low coarticulatory resistance compared to the velar counterpart. We use locus equations to analyze the coarticulatory effects. First order locus equations were used in a [aCV_] context, where C is a labial, alveolar, or velar stop, while the following V is one of the corner vowels /a,i,u/. Unlike the hypothesis, the least amount of coarticulatory resistance is shown by the velars and the alveolars show greater resistance compared to the velars and the labials. This poses an interesting question because it has been stated that mostly the slopes are seen to be order of labial, then velar and then alveolar. The possible explanations are discussed.The nature and extent of coarticulation and coarticulatory resistance of speech segments have been found to be dependent on the size, shape, and density of contrasts, in addition to neighborhood densities of segment sequences. While high density of contrasts leads to high coarticulatory resistance, low density of contrasts leads to low coarticulatory resistance. Assamese, an Indo-Aryan (IA) language, unlike the other IA languages which exhibit a two-way coronal place contrast, contains only an alveolar stop. Due to the relative low density of the alveolar, we hypothesize that the Assamese alveolar stops will exhibit low coarticulatory resistance compared to the velar counterpart. We use locus equations to analyze the coarticulatory effects. First order locus equations were used in a [aCV_] context, where C is a labial, alveolar, or velar stop, while the following V is one of the corner vowels /a,i,u/. Unlike the hypothesis, the least amount of coarticulatory resistance is shown by the velars and the alveo...

Nasal coarticulation in Bininj Kunwok: An aerodynamic analysis

Bininj Kunwok (BKw), a language spoken in Northern Australia, restricts the degree of anticipatory nasalization, as suggested by previous aerodynamic and acoustic analyses (Butcher 1999). The current study uses aerodynamic measurements of speech to investigate patterns of nasalization and nasal articulation in Bininj Kunwok to compare with Australian languages more generally. The role of nasal coarticulation in ensuring language compre-hensibility a key question in phonetics research today is explored. Nasal aerodynamics is measured in intervocalic, word-medial nasals in the speech of five female speakers of BKw and data are analyzed using Smoothing Spline Analysis of Variance (SSANOVA) and Functional Data Analysis averaging techniques. Results show that in a VNV sequence there is very little anticipatory vowel nasalization with no restriction on carryover nasalization for a following vowel. The maximum peak nasal flow is delayed until the oral release of a nasal for coronal articulations, indicating a delayed velum opening gesture. Patterns of anticipatory nasalization appears similar to nasal airflow in French non-nasalized vowels in oral vowel plus nasal environments (Delvaux et al. 2008). Findings show that Bininj Kunwok speakers use language specific strategies in order to limit anticipatory nasalization, enhancing place of articulation cues at a site of intonational prominence which also is also the location of the majority of place of articulation contrasts within the language. Patterns of airflow suggest enhancement and coarticulatory resistance in prosodically prominent VN and VNC sequences which we interpret as evidence of speakers maintaining a phonological contrast to enhance place of articulation cues.

An ultrasound study of contextual and syllabic effects in consonant sequences produced under heavy articulatory constraint conditions

The present ultrasound study investigates lingual coarticulatory resistance and differences in tongue configuration and contextual variability for consonants in syllable onset vs coda position in Catalan /iC#Ci/ sequences. In agreement with comparable ultrasound data for /aC#Ca/ sequences reported in an earlier study, coarticulatory resistance turned out to be less for /r/ (which is realized as a trill in onset position and exhibits a more tap-like realization in coda position), /l/ (which is not strongly dark), /s/ and the alveolopalatal /ɲ/ than for /p, t, n, k/. As expected, contextual variability was less for /iC#Ci/ than for /aC#Ca/ sequences due to the highly demanding requirements put on the tongue body by the high front vowel. Regarding the syllable-position-dependent differences, consonants were often longer but not less variable articulatorily in syllable initial than syllable final position. Syllable-position differences in lingual configuration could be ascribed to either a trend for consonants to be more prominent in onset vs coda position or to prominent coarticulatory effects from flanking /i/ rather than from the contextual consonant in the cluster. The conclusion is drawn that the reason why consonants may sound more reduced in coda vs onset position in heterosyllabic clusters is due less to their actual lingual configuration than to their being manifestly shorter and to specific production characteristics which depend not only on the upper articulators but on the jaw cycle as well.

Leveraging audiovisual speech perception to measure anticipatory coarticulation.

A noninvasive method for accurately measuring anticipatory coarticulation at experimentally defined temporal locations is introduced. The method leverages work in audiovisual (AV) speech perception to provide a synthetic and robust measure that can be used to inform psycholinguistic theory. In this validation study, speakers were audio-video recorded while producing simple subject-verb-object sentences with contrasting object noun rhymes. Coarticulatory resistance of target noun onsets was manipulated as was metrical context for the determiner that modified the noun. Individual sentences were then gated from the verb to sentence end at segmental landmarks. These stimuli were presented to perceivers who were tasked with guessing the sentence-final rhyme. An audio-only condition was included to estimate the contribution of visual information to perceivers' performance. Findings were that perceivers accurately identified rhymes earlier in the AV condition than in the audio-only condition (i.e., at determiner onset vs determiner vowel). Effects of coarticulatory resistance and metrical context were similar across conditions and consistent with previous work on coarticulation. These findings were further validated with acoustic measurement of the determiner vowel and a cumulative video-based measure of perioral movement. Overall, gated AV speech perception can be used to test specific hypotheses regarding coarticulatory scope and strength in running speech.

Quantifying lingual coarticulation in German using mutual information: An ultrasound study.

In previous research, mutual information (MI) was employed to quantify the physical information shared between consecutive phonological segments, based on electromagnetic articulography data. In this study, MI is extended to quantifying coarticulatory resistance (CR) versus overlap in German using ultrasound imaging. Two measurements are tested as input to MI: (1) the highest point on the tongue body and (2) the first coefficient of the discrete Fourier transform (DFT) of the whole tongue contour. Both measures are used to examine changes in coarticulation between two time points during the syllable span: the consonant midpoint and the vowel onset. Results corroborate previous findings reporting differences in coarticulatory overlap in German and across languages. Further, results suggest that MI used with the highest point on the tongue body captures distinctions related both to place and manner of articulation, while the first DFT coefficient does not provide any additional information regarding global (whole tongue) as opposed to local (individual articulator) aspects of CR. However, both methods capture temporal distinctions in coarticulatory resistance between the two time points. Results are discussed with respect to the potential of MI measure to provide a way of unifying coarticulation quantification methods across data collection techniques.

Focus and boundary effects on coarticulatory vowel nasalization in Korean with implications for cross-linguistic similarities and differences.

This study investigates focus and boundary effects on Korean nasal consonants and vowel nasalization. Under focus, nasal consonants lengthen in CVN# but shorten in #NVC, enhancing [nasal] vs [oral]. Vowels resist nasalization under focus, enhancing [oral]. Domain-initial nasal consonants denasalize, exercising no coarticulatory influence. Domain-final nasal consonants shorten counter to expectation, although vowel nasalization increases. Comparison with English data reveals similarities (focus-induced coarticulatory resistance) despite cross-linguistic differences in marking prominence, but it also suggests that prosodic-structural conditioning of non-contrastive vowel nasalization, albeit based on phonetic underpinnings of coarticulatory process, is fine-tuned in language-specific ways, resulting in cross-linguistic variation.

Evidence for active cavity expansion through advanced lingual place of constriction in voiced geminates

Geminate voicing requires both active and passive cavity expansion in order to delay the equalization of subglottal and supraglottal pressure (Ohala 1983, Ham 2001). Studies report differences in stop closure duration (Lahiri & Hankamer 1988) and pre-geminate vowel duration as cues to the laryngeal contrast. Following Schroeder (1967), Mermelstein (1967), and Iskarous (2010), we present results from formant transitions in the VC:V context and the anti-symmetric Fourier component coefficient, an = -2 (Fn-fn)/fn, to partially recover the area function of the vocal tract behind the geminate constriction. Voiced geminates exhibit significantly higher and positive coefficient values than their voiceless counterparts which implies that measured Fn values for voiced geminates are lower than their neutral tract formant values. This finding indicates that voiced geminates have a more anterior constriction compared to their voiceless counterparts. Without ruling out the role of passive cavity expansion through the cheek muscles, we conclude that in order to delay the pressure equalization the lingual constriction in voiced geminates is maintained at an anterior location compared to voiceless geminates in Bangla. Results from the slopes of first order F2 locus-equations are also presented to measure the differences in coarticulatory resistance between the voiced and voiceless geminates.Geminate voicing requires both active and passive cavity expansion in order to delay the equalization of subglottal and supraglottal pressure (Ohala 1983, Ham 2001). Studies report differences in stop closure duration (Lahiri & Hankamer 1988) and pre-geminate vowel duration as cues to the laryngeal contrast. Following Schroeder (1967), Mermelstein (1967), and Iskarous (2010), we present results from formant transitions in the VC:V context and the anti-symmetric Fourier component coefficient, an = -2 (Fn-fn)/fn, to partially recover the area function of the vocal tract behind the geminate constriction. Voiced geminates exhibit significantly higher and positive coefficient values than their voiceless counterparts which implies that measured Fn values for voiced geminates are lower than their neutral tract formant values. This finding indicates that voiced geminates have a more anterior constriction compared to their voiceless counterparts. Without ruling out the role of passive cavity expansion through the ...

Contextual and syllabic effects in heterosyllabic consonant sequences. An ultrasound study

The present ultrasound study investigates lingual coarticulatory resistance for consonants in Catalan C#C sequences. In agreement with the initial expectations, the labial /p/, the dentoalveolars /t, n, l/ and the velar /k/ turned out to be more variable than /s/, the alveolar trill /r/ and the alveolopalatal /ɲ/. Moreover, in comparison to ultrasound data for VCV sequences reported in an earlier study, consonants were less contextually variable as a general rule and this difference was most apparent at the back of the vocal tract in particular for /s/ and /r/. While consonants were generally longer syllable initially than syllable finally, differences in tongue position and contextual variability between the two syllable positions were determined by the place and manner of articulation characteristics of the target and contextual consonants rather than by a trend for consonants to exhibit a higher/more anterior and less variable tongue position when occurring in syllable onset than in syllable coda. Regarding contextual variability, /t, n, l/ showed no clearcut differences as a function of syllable position, and /s, r/ and to a large extent /p/ were more variable syllable initially and /k/ syllable finally. On the other hand, differences in tongue configuration between the two syllable sites were associated mainly with carryover tongue raising/fronting effects exerted by contextual dorsal consonants and with anticipatory tongue lowering/backing effects from the low vowel /a/ following the cluster. The dorsovelar consonant /k/ was found to blend before /ɲ/ in the sequence /kɲ/ but not in the reverse cluster /ɲk/. The implications of the present data for phonology and sound change are discussed.

Effect of speaker’s age on perceivers’ ability to predict rounding from AV speech

We have developed a noninvasive method that synthesizes the complex activity of speaking into a single measure to investigate the scope of anticipatory behavior as this relates to units of execution (Redford, Bogdanov, Vatikiotis-Bateson, 2016). The method leverages work in audio-visual speech perception to identify degree of anticipatory coarticulation at specific temporal locations, manipulated using a gating paradigm. The aim here was to test whether the method was robust to group differences in speakers’ age. Twenty-four college-aged adults judged the presence or absence of rounding in minimal pair sentences produced by 3 adults and 3 five-year-old children based on their AV-recorded speech, gated at different distances from the target rounded/unrounded vowel. Perceivers’ ability to correctly detect an upcoming rounded vowel varied as a function of the prevocalic consonant’s coarticulatory resistance and as a function of distance from target. There was no main effect of age group on perceivers’ accura...

An evaluation of several methods for computing lingual coarticulatory resistance using ultrasound.

The paper evaluates the efficiency of six computation methods in distinguishing lingual coarticulatory resistance among consonants and vowels using ultrasound data. This research goal is tested on a corpus of symmetrical vowel-consonant-vowel sequences composed of 10 consonants and five vowels produced by five Catalan speakers. Results show that, while the coarticulatory resistance hierarchies obtained by all methods conform largely to the predictions of the degree of articulatory constraint model of coarticulation, some (i.e., area of the articulatory zone, mean point-by-point coefficient of variation, and mean nearest neighbour distance) are somewhat more highly predictive than others (i.e., locus equation, mutual information, and highest point of the tongue dorsum). Methods differ mostly regarding the classification of consonants exhibiting intermediate degrees of coarticulatory resistance due to the way the methods have been designed. The implications of these findings for research on dialectal variation are discussed.