VCV Sequences Research Articles

V -to-C coarticulation in Catalan VCV sequences: an articulatory and acoustical study

Electropalatographic and acoustical data on VCV sequences for Catalan consonants involving contrasting degrees of tongue-dorsum contact (dorsopalatal [j], alveolo-palatals [ɲ] and [ʎ], and alveolar [n]) show that the degree of V-to-C coarticulation varies monotonically and inversely with the degree of tongue-dorsum contact and the size of the back cavity behind the place of constriction. Evidence for larger carryover than anticipatory V-to-C effects is also presented. Both findings suggest that, to a large extent, coarticulation on tongue-dorsum contact is regulated by mechanical constraints on articulatory activity.

A kinematic study of lingual coarticulation in VCV sequences.

Intra-articulator anticipatory and carryover coarticulation were assessed in both temporal and spatial terms. Three subjects produced VCV sequences with velar stop consonants and back vowels. Pulsed ultrasound was used to examine the vertical displacement, duration, and maximum velocity of the tongue dorsum raising (VC transition) and lowering (CV transition) gestures. Anticipatory coarticulation was primarily temporal for two subjects, with decreases in the duration of the VC transition accompanying increases in displacement for the CV transition. Carryover coarticulation was primarily spatial for all three subjects, with decreases in CV displacement and maximum velocity accompanying increases in VC displacement. It is suggested that these intra-articulator patterns can be accounted for in terms of an interaction between the raising gesture and a vowel-specific onset time of the lowering gesture towards the vowel. The implications of this kinematic characterization are discussed.

On identifying syllable boundaries

The interposition of a constant between vowels has been shown to affect systematically the formant frequencies of those vowels. The nature of these effects appears to depend on the extent to which the vowels and consonants share the tongue and lips as articulators. Traditional articulatory descriptions suggest two alternatives concerning the status of [h] and of [?] as consonants. On the one hand, since they are classified as consonants, we would expect them to produce the same coarticulatory effects as other fricatives and stops. On the other hand, since they are described as nonlingual/labial in their articulation, we would expect them to produce minimal coarticulatory effects. Indeed, results of some recent studies of speech production suggest that neither [h] nor [?] interrupts V‐to‐V articulations in the way that other consonants do (Harris and Bell‐Berti, 1982). The present study employed spectrographic analysis of VV, VhV, V?V, and VCV sequences. Results revealed that there was minimal coarticulation between [h] or [?] and the surrounding vowels. Indeed, the formant structure of the vowels in VhV and V?V sequences were more similar to those of VV sequences than to those of other VCV sequences. Since consonants are often portrayed as the units that delimit syllables, these results raise the question of functional homogeneity within the class of consonants. [Research supported by NINCDS.]

On identifying syllable boundaries

The interposition of a constant between vowels has been shown to affect systematically the formant frequencies of those vowels. The nature of these effects appears to depend on the extent to which the vowels and consonants share the tongue and lips as articulators. Traditional articulatory descriptions suggest two alternatives concerning the status of [h] and of [?] as consonants. On the one hand, since they are classified as consonants, we would expect them to produce the same coarticulatory effects as other fricatives and stops. On the other hand, since they are described as nonlingual/labial in their articulation, we would expect them to produce minimal coarticulatory effects. Indeed, results of some recent studies of speech production suggest that neither [h] nor [?] interrupts V‐to‐V articulations in the way that other consonants do (Harris and Bell‐Berti, 1982). The present study employed spectrographic analysis of VV, VhV, V?V, and VCV sequences. Results revealed that there was minimal coarticulation between [h] or [?] and the surrounding vowels. Indeed, the formant structure of the vowels in VhV and V?V sequences were more similar to those of VV sequences than to those of other VCV sequences. Since consonants are often portrayed as the units that delimit syllables, these results raise the question of functional homogeneity within the class of consonants. [Research supported by NINCDS.]

Lingual coarticulation in VCV sequences

Pulsed‐echo ultrasound was used to study coarticulation in tongue dorsum movements during the production of VCV sequences. The stimuli were velar stop consonants /k/ and /g/ combined with posterior vowels /a/, /o/, and /u/. Vertical displacement, maximum velocity, and duration were obtained for all V1C and CV2 transitions. Right‐left (effect of CV2 on V1C) and left‐right (effect of V1C on CV2) coarticulation Was examined by stepwise multiple regression. Highly significant effects were obtained with /a/. Total duration of V1C was negatively related both to displacement from linguo‐palatal contact to the point of maximum velocity and to total displacement of CV2 (RL effects). Total displacement and maximum velocity of CV2 were negatively related to the displacement to the point of maximum velocity and total displacement of V1C (LR effects). The LR effects of V1C on CV2 were larger than the corresponding RL effects. Similar patterns were obtained for both intervocalic consonants. The findings are discussed in terms of the contributions of mechano‐inertial and motor timing effects to coarticulation.

Labial coarticulation in some French VCV sequences measured by electromyographic and cinematographic techniques

The purpose of this study is to know anticipatory and carryover labial coarticulatory effects during the production of certain french vowel‐sibilant‐vowel sequences. These effects are defined on EMG activity correlated with lip gesture estimated from a film. EMG data are attained from orbicularis oris inferior, mentalis, depressor labii inferioris, levator labii superioris alaeque nasi of two subjects through the use of paint‐on electrodes. Three groups of syllables are defined. Not very protruded syllables [∫i, ȝi, ∫e, ȝe] are characterized by an anticipatory and carryover labial coarticulation with activity of mentalis and orbicularis oris inferior corresponding to protrusion, only if preconsonantal vowel is (−lab]. As concern protruded syllables [sy, zy, so, zo] in a [−lab]preconsonantal context, the influence [+lab] of vowel begins during the production of sibilant with mentalis activity and protrusion. In a [+lab]preconsonantal context, mentalis activity and protrusion decrease slightly during the pr...

Articulatory movements in VCV sequences.

The purpose of this experiment was to study both the timing and positional properties of articulatory movements in VCV utterances. Conventional cinefluorographic techniques were used to track the movements of the upper lip, lower lip, jaw, tongue tip, and tongue body of two speakers who read randomized lists of VCV utterances containing the vowels /i,a,u/ and the consonants /p,t,k/, in all possible combinations. Results showed that the timing of articulatory movements in a VCV sequence are constrained by the intervocalic consonant, even if the gesture for the consonant is not a contradictory one. Anticipatory movements toward the second vowel always begin during the closure period of the intervocalic consonant. The appearance of carry over coarticulation effects depends on the phonetic identity of the particular segment or degree of involvement of the articulator. Carry over effects, like anticipatory effects, did not extend beyond an immediately adjacent segment. These findings suggest that the rules governing the segmental input to a speech string might be simpler than present models suggest.

Velar coarticulation in French: a fiberscopic study

This study examines the temporal course of velar movement in French nasal consonants and nasalized vowels by fiberscopic observation. The utterances under study were produced by a native speaker of French. They included isolated vowels, isolated CVC sequences, isolated VCV sequences, VCV sequences in a fixed frame, and specially constructed utterances. The results show that plosives, fricatives and most vowels are produced with the velopharyngeal port closed. Nasal consonants are produced with the velopharyngeal port at least partially open. Nasalized vowels are also produced with the velopharyngeal port partially open, subject to contextual constraints that may be quite severe. Some of these constraints are examined, as well as coarticulatory effects, particularly with respect to Henke's model of speech production.

Velar coarticulation in French: an electromyographic study

EMG activity was recorded from the levator veli palatini and the palatoglossus of a native speaker of French. The corpus included isolated CVC sequences, isolated VCV sequences, and specially constructed utterances. Velar control and nasalization do not appear to be controlled by a simple binary mechanism. In particular nasalized vowels and nasal consonants appear to be controlled in different ways. Anticipatory coarticulation is observed in numerous instances, whereas carryover coarticulation is not observed in the case of EMG suppression. No syllable boundary effect was observed for coarticulation. This is in agreement with other data on French, but not with data on Japanese.

An electropalatographic investigation of coarticulation in VCV sequences

Tongue-palate contact during three subjects’ pronunciation of 18 VCV nonsense words was recorded with the aid of an electropalatographic technique. Coarticulation within and across the intervocalic plosives is described qualitatively, in terms of resemblances between contact configurations, and quantitatively, in terms of the duration for which such coarticulations appear to extend back or forwards into the stop closure or opposite vowel. Principal findings were: (1) Coarticulatory tongue movement within certain velar closures which could give rise to air flow during stop closure. (2) More right-to-left than left-to-right coarticulation within and across both plosive types. (3) A coarticulatory hierarchy among the vowels investigated such that [i] exerts the greatest coarticulatory influence and [a] the least. (4) Coarticulation across closures from one vowel to the other, but more frequently with alveolare than with velars. (5) Considerable inter-individual differences which emphasize the need to investigate larger numbers of subjects.

On the perception of coarticulation effects in English VCV syllables.

Ohman’s 1966 investigation of the acoustic correlates of coarticulation in VCV sequences indicates that terminal formant frequency transition values are strongly influenced by the nature of the transconsonantal vowel. This experiment was designed to explore the perceptual correlates of Ohman’s spectrographic findings. We discovered that when a VCV sequence (where C is a voiceless plosive) is cut in two during the period of consonantal closure, there are not enough remaining cues in either the resulting VC or CV sequences to allow for identification of the deleted segment or of its articulatory features. However, it appears that coarticulation effects may hinder recognition of nonfinal allophones placed artificially in final position. Consonants in VC sequences spliced from original VCV utterances are more difficult to identify than unreleased final consonants of the same quality.

Perception of Coarticulation in English VCV Sequences

Öhman's 1966 investigation of the acoustic correlates of coarticulation in Swedish and English VCV sequences [J. Acoust. Soc. Amer. 39, 151–168 (1966)] indicates that terminal formant transition frequency values are strongly influenced by the nature of the transconsonantal vowel. However, the literature reflects no attempts to discover whether these coarticulation effects are perceptible, e.g., whether in a VCV sequence the initial VC carries significant perceptual cues as to the quality of the following V. The present experiment was designed to investigate the latter question. Forty-eight VCV utterances involving the vowels /i æ a u/ and the consonants /p t k/ were recorded and either the initial or final vowel removed by splicing techniques. The resulting tapes were played to listeners who were asked to indicate which vowel had been deleted. Results were random indicating that coarticulation effects are not sufficient cues to the perception of the vowels which occasion them. These results are counterevidence for the claim by Wickelgren [Psychol. Rev. 76, No. 1, 1–15 (1969)] that the “context sensitive” allophone may be a basic cue in speech recognition. The results also suggest that some coarticulation effects may not have to be taken into consideration in speech synthesis.