Articulatory Correlates Research Articles

Exposure to Canadian French Cued Speech Improves Consonant Articulation in Children With Cochlear Implants: Acoustic and Articulatory Data.

One of the strategies that can be used to support speech communication in deaf children is cued speech, a visual code in which manual gestures are used as additional phonological information to supplement the acoustic and labial speech information. Cued speech has been shown to improve speech perception and phonological skills. This exploratory study aims to assess whether and how cued speech reading proficiency may also have a beneficial effect on the acoustic and articulatory correlates of consonant production in children. Eight children with cochlear implants (from 5 to 11 years of age) and with different receptive proficiency in Canadian French Cued Speech (three children with low receptive proficiency vs. five children with high receptive proficiency) are compared to 10 children with typical hearing (from 4 to 11 years of age) on their production of stop and fricative consonants. Articulation was assessed with ultrasound measurements. The preliminary results reveal that cued speech proficiency seems to sustain the development of speech production in children with cochlear implants and to improve their articulatory gestures, particularly for the place contrast in stops as well as fricatives. This work highlights the importance of studying objective data and comparing acoustic and articulatory measurements to better characterize speech production in children.

Tongue position in Mandarin Chinese voiceless stops.

The current study explores whether Mandarin initial and medial voiceless unaspirated and voiceless aspirated stops differ in their tongue positions and post-vocalic voicing during closure. Ultrasound tongue imaging and acoustic data from five Mandarin speakers revealed (1) no consistent pattern for tongue positions among speakers, and (2) no difference in degree of voicing during closure between the two stop series. These findings suggest that tongue position is not a reliable articulatory correlate for Mandarin laryngeal contrasts. This further suggests that aspiration is not correlated with tongue position differences, unlike the reported correlation between voicing and tongue root advancement.

Edge strengthening and phonetic variability in Spanish /l/: an ultrasound study.

Previous research has shown that /l/ in Spanish displays patterns of articulatory variability that are determined by a complex interaction of phonetic, phonological and dialectal factors. In this study, we report the results of an experiment using Ultrasound Tongue Imaging (UTI) that tests /l/-articulations in a dialectal cross-section of Spanish speakers. We show that lengthening of /l/ in phrase-edge contexts is accompanied by articulatory distinctions (e.g. root/dorsum retraction) for some speakers, whereas others produce lengthened realisations of /l/ in these contexts without observable differences in tongue position. We also find acoustic evidence for reduction in utterance-medial intervocalic and preconsonantal environments (duration, intensity, F1 frequency measures are discussed). However, articulatory correlates of reduction are not consistently observed across speakers in these contexts. As well as relating the results to prosodically-driven strengthening and reduction patterns, our findings are of relevance to debates about resyllabification in Spanish. Specifically, we argue that our results cannot be straightforwardly accommodated under phonological analysis assuming that word-final consonants regularly resyllabify across word boundaries prevocalically.

Audio-visual clear speech: Articulation, acoustics and perception of segments and tones

Research has established that clear speech with enhanced acoustic signal benefits segmental intelligibility. Less attention has been paid to visible articulatory correlates of clear-speech modifications, or to clear-speech effects at the suprasegmental level (e.g., lexical tone). Questions thus arise as to the extent to which clear-speech cues are beneficial in different input modalities and linguistic domains, and how different resources are incorporated. These questions address the fundamental argument in clear-speech research with respect to the trade-off between effects of signal-based phoneme-extrinsic modifications to strengthen overall acoustic salience versus code-based phoneme-specific modifications to maintain phonemic distinctions. In this talk, we report findings from our studies on audio-visual clear speech production and perception, including vowels and fricatives differing in auditory and visual saliency, and lexical tones believed to lack visual distinctiveness. In a 3-stream study, we use computer-vision techniques to extract visible facial cues associated with segmental and tonal productions in plain and clear speech, characterize distinctive acoustic features across speech styles, and compare audio-visual plain and clear speech perception. Findings are discussed in terms of how speakers and perceivers strike a balance between utilizing general saliency-enhancing and category-specific cues across audio-visual modalities and speech styles with the aim of improving intelligibility.

The emergence of bunched vowels from retroflex approximants in endangered Dardic languages

Abstract Kalasha, an endangered Dardic (Indo-Aryan) language, contrasts a rich set of rhotic vowels, a vowel type, which is found in less than 1% of the world’s languages. The acoustic and articulatory correlates of rhotic vowels, and their development and geographical distribution in Kalasha and other Indo-Iranian languages are still poorly understood. The current study brings together typological data on retroflex approximants and flaps in 192 Indo-Iranian language varieties, and phonetic data on rhotic vowels and retroflex approximants in endangered Dardic (Kalasha and Dameli) and Nuristani (Kamviri and Eastern Kataviri) languages. The phylogeography of retroflex approximants and flaps indicates that rhotic vowels are prevalent in those areas of South Asia where retroflex approximants are in abundance. Specifically, the development of rhotic vowels in Kalasha may have been amplified by the presence of retroflex approximants in neighboring Nuristani languages. We show that phonetically the rhotic sounds in the two Dardic languages are produced with a bunched tongue shape, whereas the retroflex approximants in Nuristani languages are produced with the raising of the tongue tip.

Phonetic and phonological properties of the advanced tongue root feature in African languages

The paper presents an overview of the ATR (advanced tongue root) feature, which is fairly widespread among the Niger-Congo and Nilo-Saharan languages of the Macro-Sudan Belt. The phonetic section provides a description of the articulatory and acoustic correlates of the feature. The review of the articulatory basis of the feature is presented in a historical perspective, from the fi rst cineradiographic studies of the 1960s till the laryngoscopic studies of the recent years. The paper shows how the introduction of new methods shifted attention from the tongue root movement, which had been given primacy in production of the contrast, to aryepiglotto-epiglottal constriction and a synergistic system of laryngeal articulations. The paper provides a description of several acoustic measures that have been found to correlate with the ATR feature: the frequency of the fi rst formant, the fi rst formant bandwidth, the spectral center of gravity, the relative intensity of the fi rst to the second formant. Similarities and differences between ATR, height and tenseness, which have been largely discussed in the literature, are also described in the paper. The phonological section provides an overview of ATR harmony systems. The main attention is paid to the strong crosslinguistic tendency for [+ATR] to function as the dominant value in languages with ATR contrast among high vowels, but for [−ATR] to be dominant in languages in which ATR is only contrastive for non-high vowels. The paper describes diff erent manifestations of ATR dominance (assimilatory, allophonic, and coalescent dominance) among two major types of underlying vowel inventories.

A dual mechanism for intrinsic f0

Vowel-intrinsic fundamental frequency (IF0), the phenomenon that high vowels tend to have a higher fundamental frequency (f0) than low vowels, has been studied for over a century, but its causal mechanism is still controversial. The most commonly accepted “tongue-pull” hypothesis successfully explains the IF0 difference between high and low vowels but fails to account for gradient IF0 differences among low vowels. Moreover, previous studies that investigated the articulatory correlates of IF0 showed inconsistent results and did not appropriately distinguish between the tongue and the jaw. The current study used articulatory and acoustic data from two large corpora of American English (44 speakers in total) to examine the separate contributions of tongue and jaw height on IF0. Using data subsetting and stepwise linear regression, the results showed that both the jaw and tongue heights were positively correlated with vowel f0, but the contribution of the jaw to IF0 was greater than that of the tongue. These results support a dual mechanism hypothesis in which the tongue-pull mechanism contributes to raising f0 in non-low vowels while a secondary “jaw-push” mechanism plays a more important role in lowering f0 for non-high vowels.

Articulatory activity of the tongue, jaw, and lips during the second passaggio acoustic transition of female singers

Sopranos typically exhibit an acoustic modification between 600 and 700 Hz (on /a/) during which second resonance (R2) tracking of the second harmonic (2fo) changes to first resonance (R1) tracking of the fundamental (fo). To quantify the alteration, the sound pressure level difference between the first two harmonics (L1-L2) was measured for chromatic scales sung between C5◻ and G5◻ (523 to 784 Hz) by 17 sopranos (9 judged by the first author as “techniqued” and 8 as “un-techniqued” and confirmed by perceptual experiment). Techniqued sopranos shifted from negative to positive values of L1-L2 as early as D5◻ (587 Hz), while the least techniqued singers did not make the change at all. Articulatory correlates were measured using ultrasound of the tongue and optical tracking. Head-corrected tongue contours showed the most critical articulatory factor to be the size of a triangular area between two points on the hard palate and the most anterior tongue point. Sopranos who made the change earliest exhibited the largest anterior oral cavities whereas sopranos who never made the acoustic change had significantly smaller anterior cavities. Larger anterior oral cavities appear to accommodate lower frequencies of R2, presumably lowering L2 and increasing L1-L2. [Work supported by NIH grant DC-002717.]

An acoustic and articulatory study of laryngeal and place contrasts of Kalasha (Indo-Aryan, Dardic).

The Northwestern group of Indo-Aryan (Dardic) languages is generally known to have undergone consonantal shift, which resulted in the loss of voiced aspirated (VDA) stops and affricates of Sanskrit. Kalasha, an endangered Dardic language spoken in Chitral (Northern Pakistan), still preserves the Old Indo-Aryan four-way laryngeal system. The current study examines acoustic and articulatory correlates of Kalasha's four-way laryngeal contrast across places and manners of articulation, using lingual ultrasound-imaging and several acoustic measures. The analysis included the standard acoustic [voice onset time (VOT), after prevoicing interval (API), fundamental frequency onset, first four spectral moments] and articulatory (smoothing spline analysis of variance) measures, which capture laryngeal, place, and manner differences in consonants. The results showed that VOT reliably differentiated the four-way laryngeal contrast of Kalasha. VDA stops and affricates are characterized by shorter voicing lead VOT, higher API, and lower fundamental frequency onset than their voiced unaspirated (VDUA) counterparts. However, the first four spectral moments did not distinguish the two VDUA and VDA stop series. The tongue root retraction distinguishes the voiceless stops and affricates from the voiced ones.

Distinguishing breathy consonants and vowels in Gujarati

Abstract Across languages, the acoustic and articulatory correlates of breathiness are similar whether they are associated with consonants or with vowels. This raises the question of whether breathy consonants are confusable with breathy vowels in languages in which a phonemically breathy vowel contrasts with a phonemically modal vowel that follows a breathy-aspirated consonant, e. g. Gujarati /ba̤ɾ/ ‘outside’ vs. /bʱaɾ/ ‘burden’, respectively. We investigate the perception of a minimal triplet of Gujarati words, with a breathy vowel vs. a breathy consonant vs. an all-modal sequence, via three tasks: free-sort, AX discrimination, and picture-matching identification. Results across the three tasks indicate that breathiness is indeed confusable across the association types. Specifically, while listeners do recognize the stronger breathiness in vowels following breathy consonants, they are not necessarily able to determine whether that breathiness is associated with the vowel or the consonant. Furthermore, they do not reliably recognize the subtler breathiness of breathy vowels, which often indicates that they are the same as or an acceptable realization of an all-modal sequence (/baɾ/ ‘twelve’). This suggests a potential perceptual merger in Gujarati, despite previously-reported evidence of a robust three-way contrast in production.

Articulatory characteristics of focus in Korean

The phonetic correlates of prominence in head prominence languages (e.g., English), where prominence is signaled by stress and pitch accent, are extensively studied. However, the phonetic profile of prominence in edge prominence languages, such as Korean, that realize prominence by phrasing is not well understood. Relevant work has mainly focused on the acoustic domain and boundary-related phenomena. The present study assesses the articulatory correlates of prominence in Seoul Korean by the means of electromagnetic articulography (EMA). Specifically, we examine the effect of presence of focus (contrastive focus versus absence of focus) and position of focus (initial versus final) on the consonant constriction gestures of utterances consisting of two four-syllable long accentual phrases (APs). Preliminary results suggest that constriction gestures are longer, faster, and, although weakly supported, larger in contrastive focus than in the unfocused condition. These effects are found on the onset consonants of the first two syllables of the focused AP when the latter is utterance-initial, but extend to the coda of the second syllable when focus is on the final AP. A theoretical account of prominence and its interaction with boundaries in edge-marking languages is proposed, with implications for a cross-linguistic model of prosody. [Work supported by NSF.]

The role of tongue position in laryngeal contrasts: An ultrasound study of English and Brazilian Portuguese

Many languages make a two-way laryngeal contrast in obstruents, but the phonological and phonetic characterization of these contrasts continues to be controversial. In English, utterance-initial /b d ɡ/ stops are often phonetically voiceless. Languages like Brazilian Portuguese, however, exhibit phonetic voicing for /b d ɡ/ stops utterance-initially. This study focuses on tongue position as an articulatory correlate of laryngeal contrasts. Results of an ultrasound study show that tongue position differences are similar for English and Portuguese despite VOT differences, although English speakers show more variation. Tongue root advancement/tongue body lowering is found in both English and Portuguese /b d ɡ/ stops, compared to /p t k/ counterparts. In addition to VOT, which reflects the timing of the oral and laryngeal gestures, the tongue position during closure may be an integral part of the articulatory properties of laryngeal contrasts. Results imply that these languages have different laryngeal gestures but share a similar supralaryngeal articulatory gesture, which may be necessary to distinguish between /b d ɡ/ and /p t k/ stops with respect to supralaryngeal cavity volume.

Articulatory correlates of the acoustic transition during the second passaggio of sopranos

The present experiment examines articulatory correlates associated with the presence or absence of a change in A1-A2, the amplitude difference between the first two harmonics (fo and 2fo),in the second passaggio transition (D5♮ to F5♮, or 587 to 698 Hz) of the soprano voice. An earlier investigation of this area in a classical, techniqued soprano singing on a low vowel revealed a change from negative to positive values in A1-A2 at a pivot point between E5♭ and E5♮. But when the same singer produced sounds without technique, the A1-A2 values remained negative. The present articulatory investigation uses ultrasound and optical tracking for analysis of head-corrected tongue contours, jaw opening, lip aperture, and lip protrusion that accompany the presence or absence of the acoustic change in this same singer. Preliminary results replicate the relationship between the acoustic change from negative to positive values of A1-A2 and show a substantial change in tongue dorsum height. In contrast, singing that exhibits only negative values of A1-A2 shows no such articulatory changes. The same experimental protocol was then used with sopranos who can and cannot make the A1-A2 acoustic change. Acoustic and articulatory results will be reported. [Funded by NIH grant DC-002717.]

Articulatory correlates of phonemic and coarticulatory nasalization

Phonological theory distinguishes nasal and oral vowel counterparts by velopharyngeal port opening, neglecting other phonetic differences between phonemic and coarticulatory nasalization. Recent articulatory work provides evidence of oropharyngeal distinctions, in addition to velic lowering. This study (12 Brazilian Portuguese speakers) uses real-time MRI to investigate oropharyngeal differences between oral, phonemically nasal, and phonetically nasalized vowels /a, i, u/. Tissue boundaries in midsagittal vocal tract images were automatically detected to reveal each vowel repetition’s aperture function. Principal Components Analysis determined vocal tract regions responsible for the greatest variance in the data. Time-dynamic analyses of vocal tract area in these regions used smoothing spline ANOVA. Results show the tongue body and/or hyperpharynx as the most important articulators. For /a/, nasal vowels demonstrate wider hyperpharyngeal and narrower tongue body regions compared to oral vowels. For /u/, o...

An acoustic-articulatory study of bilingual vowel production: Advanced tongue root vowels in Twi and tense/lax vowels in Ghanaian English

This article investigates the acoustic and articulatory correlates of vowel contrasts in bilingual speakers. We analyse data from bilingual speakers of Twi (Akan) and Ghanaian English, with the aim of examining how the production of the advanced tongue root vowel contrast in Twi relates to the production of the tense/lax vowel contrast in Ghanaian English. These data are compared to tense/lax vowel data from monolingual British English speakers. The acoustic results show that Twi and Ghanaian English mainly rely on F1 for distinguishing [ATR] and [TENSE] vowels, whereas British English uses F1, F2, F3 and duration for the [TENSE] contrast. The ultrasound tongue imaging data show tongue root distinctions across all languages, while there are consistent tongue height distinctions in British English, no height distinctions in Ghanaian English, and small height distinctions for some vowels in Twi. Twi has the weakest correlation between F1 and tongue root advancement, which suggests that the [ATR] contrast may involve additional strategies for pharyngeal cavity expansion that are not present in [TENSE] vowels. In doing so, we show that bilinguals produce similar contrasts in similar ways across their two languages, but that language-specific differences also persist, which may reflect different articulatory goals in each language.

Articulatory correlates of metrical structure: Studying jaw displacement patterns

AbstractPrevious phonetic studies of metrical prominence have primarily focused on its acoustic manifestations, including pitch, intensity, duration, spectral tilt, etc. In this paper we outline our new research program in which we explore jaw displacement patterns as another articulatory reflex of metrical prominence. We present our studies of English and Japanese in some detail, which show that jaw movement patterns are neither flat nor random, but instead the degrees of jaw displacement correlate well with metrical prominence. Based on these results, we argue that there are at least two articulators to express metrical prominence: the larynx and the jaw. Our aim is not so much to object to looking at the acoustic manifestations of metrical structures or other articulation-based approaches; we instead would like to encourage other researchers to investigate metrical structure in terms of jaw movement as well.

Articulatory correlates of /w/ in Korean

The articulatory properties of /w/ have received relatively little attention compared to those of vowels and consonants. Although lip protrusion as well as dorsum raising and backing have generally been considered the major articulatory correlates of /w/, there is cross-linguistic evidence that the primary articulation of labiovelars, including /w/, is labial in some languages, while in other languages it is velar ([1]). Partly due to little articulatory data, there is little consensus on what articulatory features are involved in the production of /w/ in each language. This study used ultrasound to image tongue shapes for /w/ produced by three native Korean speakers. Also, a video camera was used to capture the movement of lips. The video data of movements of both tongue and lips were subjected to Optical Flow Analysis, a technique used to measure the magnitude of movement (MM) of objects in a video. The results show that there is prominent lip protrusion gestures for /w/ in Korean while there is little movement in tongue dorsum (the average MM of lip = 1.78; tongue = 0.48; t(86) = 4.02, p<0.001). This finding indicates that the glide /w/ in Korean involves labial movements only, contrary to the previous description of Korean glides [2], [3].

Speaking Clearly for the Blind: Acoustic and Articulatory Correlates of Speaking Conditions in Sighted and Congenitally Blind Speakers.

Compared to conversational speech, clear speech is produced with longer vowel duration, greater intensity, increased contrasts between vowel categories, and decreased dispersion within vowel categories. Those acoustic correlates are produced by larger movements of the orofacial articulators, including visible (lips) and invisible (tongue) articulators. Thus, clear speech provides the listener with audible and visual cues that are used to increase the overall intelligibility of speech produced by the speaker. It is unclear how those cues are produced by visually impaired speakers who never had access to vision. In this paper, we investigate the acoustic and articulatory correlates of vowels in clear versus conversational speech, and in sighted and congenitally blind speakers. Participants were recorded using electroarticulography while producing multiple repetitions of the ten Quebec French oral vowels in carrier sentences in both speaking conditions. Articulatory variables (lip, jaw, and tongue positions) as well as acoustic variables (contrasts between vowels, within-vowel dispersion, pitch, duration, and intensity) were measured. Lip movements were larger when going from conversational to clear speech in sighted speakers only. On the other hand, tongue movements were affected to a larger extent in blind speakers compared to their sighted peers. These findings confirm that vision plays an important role in the maintenance of speech intelligibility.

Morphological effects on the darkness of English intervocalic /l/

AbstractArticulatory and acoustic studies have provided evidence that in word- initial and word-final positions, English /l/ exhibits substantial differences in ‘darkness‐: dark [ɫ] in word-final position is produced with a more retracted tongue dorsum and lowered tongue body than light [l] in word-initial position. The darkness of intervocalic /l/, however, is variable. While Sproat and Fujimura (1993) argue that /l/ darkness is on a continuum strongly affected by duration, Hayes (2000) maintains that the morphological status of intervocalic /l/s should affect whether they are produced as light or dark variants. In this study, ultrasound imaging is used to investigate whether the morphological affiliation of the /l/ affects the degree of tongue dorsum retraction and tongue body lowering and the acoustic characteristics of /l/ darkness. Six American English speakers produced three types of stimuli which were predicted to increase in darkness in the following order: (1) when /l/ corresponded with the onset of a suffix (e.g., flaw-less), (2) when /l/ corresponded with the final position of the stem word (e.g., tall-est), and (3) when /l/ was the final consonant of a stem word (e.g., tall). For both articulatory and acoustic measures, the predicted order was upheld. The strongest articulatory correlate of darkness was tongue body lowering, and acoustic differences were mainly manifested in F1 and normalized intensity. Phonological implications of these findings are discussed.

Invariant articulatory bases of the features [tense] and [spread glottis] in Korean plosives: New stroboscopic cine-MRI data

In earlier work, we found that the fortis and aspirated coronal consonants /t h, t′, ts h, ts′, s′/ of Korean have more concomitant tongue and larynx raising than the lenis consonants /t, ts, s/ and that the aspirated consonants have greater glottal opening than the other series. The concomitant tongue and larynx raising and the glottal opening were proposed to be invariant articulatory correlates of the features [+tense] and [+spread glottis], respectively: fortis and aspirated consonants are specified as [+tense] and aspirated as [+spread glottis]; otherwise consonants are [−tense] and [−spread glottis]. The present study aims to determine whether this description generalizes to the full set of Korean plosives, including labials and dorsals. For this purpose, values of lip, tongue and jaw displacements, vertical larynx movements and glottal width in the Korean coronal and non-coronal plosive consonants /t, t h, t′, p, p h, p′, k, k h, k′/ were obtained from midsagittal and coronal MRI data from the same two native speakers as in the earlier work. It is concluded that the feature [±tense] is defined in terms of the tensing of both the primary articulator (lips, tongue blade or dorsum) and the vocal folds and that the feature [±spread glottis] is defined in terms of glottal opening, as in Halle and Stevens [(1971). A note on laryngeal features. Quarterly progress report (vol. 101, pp. 198–212). Cambridge, MA: Research Laboratory of Electronics, MIT]. These attributes appear to be invariant in Korean, as long as we interpret invariance as relative rather than absolute. This model is shown to provide a better fit to the phonetic data than several alternative proposals.