Postvocalic Consonants Research Articles

Interaction between Phrasal Structure and Vowel Tenseness in German: An Acoustic and Articulatory Study.

Phrase-final lengthening affects the segments preceding a prosodic boundary. This prosodic variation is generally assumed to be independent of the phonemic identity. We refer to this as the 'uniform lengthening hypothesis' (ULH). However, in German, lax vowels do not undergo lengthening for word stress or shortening for increased speech rate, indicating that temporal properties might interact with phonemic identity. We test the ULH by comparing the effect of the boundary on acoustic and kinematic measures for tense and lax vowels and several coda consonants. We further examine if the boundary effect decreases with distance from the boundary. Ten native speakers of German were recorded by means of electromagnetic articulography (EMA) while reading sentences that contained six minimal pairs varying in vowel tenseness and boundary type. In line with the ULH, the results show that the acoustic durations of lax vowels are lengthened phrase-finally, similarly to tense vowels. We find that acoustic lengthening is stronger the closer the segments are to the boundary. Articulatory parameters of the closing movements toward the post-vocalic consonants are affected by both phrasal position and identity of the preceding vowel. The results are discussed with regard to the interaction between prosodic structure and vowel tenseness.

Perception of English Tense and Lax Vowels according to Voicing Contrast in Postvocalic Consonants by Korean Young EFL Learners

This study attempts to investigate whether Korean young EFL learners could differently perceive the difference between English tense and lax vowels (/i/-/ɪ/) with the voicing contrast in the postvocalic consonants. Two perception tests (4I-oddity test and Identification test) are conducted with the following research questions. 1) Do Korean young EFL learners show any difference in correctly discriminating tense and lax vowels according to the voicing contrast in postvocalic consonants at the auditory level? 2) Do they differently identify English tense and lax vowels according to voicing contrasts at the phonological level? 3) Do they differently identify English tense and lax vowels according to different manners of articulation (stops vs. fricatives)? For each experimental test, 11 Korean speakers and 5 native speakers (as a control group) participate in the study. The main findings from the tests are as follows. First, Korean learners perform as well in the 4I-oddity discrimination test as native speakers do, while more poorly performing in the identification test. Second, Korean learners did not use vowel length as an acoustic cue to differentiate between English tense and lax vowels in both perception tests regardless of voicing contrasts or manner of articulation in postvocalic consonants. According to these findings, the study concludes that the absent feature of vowel length in the L1 does not facilitate Korean speakers’ accurate perception of English tense and lax vowels at the phonological level.

On the evolution of prosodic boundaries – Parameter settings for Polish and English

Phonological descriptions often make reference to prosodic boundaries without exploring the origins of those boundaries. In the Onset Prominence representational framework, prosodic boundaries fall out from the same mechanisms that govern word-internal phonology. These mechanisms are parametric. Opposing settings for these parameters in Polish and English allow for a unified analysis of apparently diverse phonological phenomena including cluster phonotactics, the behavior of post-vocalic consonants, the realization of word-initial vowels, and the application or non-application of external sandhi.

Alphabetism and the science of reading: from the perspective of the akshara languages.

Alphabetism and the science of reading: from the perspective of the akshara languages.

Palatalization and temporal organisation of CVC clusters in Russian

The paper investigates the influence of palatalization on the temporal organization of CVC clusters. It was observed that the palatalization of prevocalic consonants increases the duration of vocalic intervals in CVC clusters if the vowel is [−front]. The palatalization of both consonants in CVC clusters decreases the duration of vocalic intervals if the vowel is [+front]. The palatalization of postvocalic consonants increases the duration of consonantal intervals in CVC clusters. The obtained results are interpreted in the light of physiological constraints on articulation that enhance the perceptual distinctiveness of phonological contrasts which involve palatalization.

The syllabic affiliation of postvocalic liquids: An onset-specifier approach

In this paper we propose that the traditional rhymal adjunct position of standard Government Phonology should be replaced by an onset-specifier position, allowing a uniform interpretation of licensing and government relations within syllabic constituents. This approach appropriately models a number of generalisations regarding the distribution of postvocalic liquids in English and other languages, and can be fruitfully extended to other postvocalic consonants, such as nasals and /s/.

Phonological Structure in Syllabification: Evidence from Dyslexia

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Perisegmental speech improves consonant and vowel identification

In two papers, Nearey (1992, 1997) discusses the fact that theories on phoneme identification generally favor strong cues that are localized in the speech signal. He proposes an alternative view in which cues to phoneme identity are relatively weak and dispersed. In the present listening experiment, Dutch subjects identified speech tokens containing fragments of vowel and consonant realizations and their immediate neighbors, taken from connected read speech. Using a measure of listener confusion based on the perplexity of the confusion matrix, it is possible to quantify the amount of information extracted by the listeners from different parts of the speech signal. Around half the information needed for the identification task was extracted from only a short, 40–50 ms, speech fragment. Considerable amounts of additional information were extracted from parts of the signal at, and beyond, the conventional boundaries of the segment, here called perisegmental speech. Speech in front of the target segment improved identification more than speech following the target segment, even if this speech was actually not part of the target phoneme itself. Correct identification of pre-vocalic consonants correlated with the correct identification of the following vowel, and vice versa. The identification of post-vocalic consonants was not correlated with the identification of the vowel in front. It is concluded that human listeners extract an important fraction of the information needed to identify phonemes from outside the conventional segment boundaries. This supports the proposal of Nearey that extended, “weak” cues might play an important part in the identification of phonemes.

The Status of Final Consonant Clusters in English Syllables: Evidence from Children

According to certain models, the syllable has an internal hierarchical structure, with the major constituents of onset (initial consonant or consonant cluster) and rime. The rime consists of the vocalic nucleus and the coda (final consonant or consonant cluster). The purpose of the present study was to collect evidence on the structure of the rime and the status of the coda as a unit, with children as subjects. In Experiment 1, children were found to have less difficulty learning a word game which kept the final consonant cluster intact compared to one which broke it up. The strength of this effect depended on the phonetic class of the postvocalic consonant, with stronger effects for nasals and obstruents than liquids. Aspects of the data indicated that nasals and obstruents behave similarly as postvocalic consonants, whereas other analyses indicated that nasals are intermediate between obstruents and liquids in terms of membership of the coda. In Experiment 2 it was shown that the more robust type of coda cluster is as coherent a unit as clusters in onset position. The data support a model which attributes internal hierarchical structure to the rime, with the coda as a constituent, although the components of the coda depend on the phonetic class of the first (i.e., postvocalic) consonant.

Modelling of phone duration (using the TIMIT database) and its potential benefit for ASR

As indicated by Bourlard et al. (1996), the best and simplest solution so far in standard ASR technology to implement durational knowledge, seems to consist of imposing a (trained) minimum segment duration, simply by duplicating or adding states that cannot be skipped. We want to argue that recognition performance can be further improved by incorporating “specific knowledge” (such as duration and pitch) into the recognizer. This can be achieved by optimising the probabilistic acoustic and language models, and probably also by a postprocessing step that is fully based on this specific knowledge. The widely available, hand-segmented, TIMIT database was used by us to extract duration regularities, that persist despite the great speaker variability. Two main approaches were used. In the first approach, duration distributions are considered for single phones, as well as for various broader classes, such as those specified by long or short vowels, word stress, syllable position within the word and within an utterance, post-vocalic consonants, and utterance speaking rate. The other approach is to use a hierarchically structured analysis of variance to study the numerical contributions of 11 different factors to the variation in duration. Several systematic effects have been found, but several other effects appeared to be obscured by the inherent variability in this speech material. Whether this specific use of knowledge about duration in a post-processor will actually improve recognition performance still has to be shown. However, in line with the prophetic message of Bourlard et al.'s paper, we here consider the improvement of performance as of secondary importance.

Timing analysis of coding and articulation processes in dyslexia.

Several investigators have found that the time required to perform serial naming tasks is a good predictor of dyslexia in children. Protracted overall time scores, such as are reported for the Rapid Automatized Naming (RAN) test of Denckla and Rudel, are, by themselves, insufficient to determine the extent to which the performance deficit is cognitive in nature, or is the articulatory consequence of an inability master the quickly changing acoustic formant patterns associated with consonants, as proposed by Tallal. We administered the RAN test to matched groups of dyslexic and normal control children, aged 8 to 11 years. Measurement of speech signal durations was performed by computer. We applied the Gould and Boies algorithm for extracting cognitive preparation time to these data, resulting in a partition of overall RAN test score into coding time and articulation time components. Differential performances between the groups on RAN subtests were examined for effects of postvocalic consonants and semantic load. It was found that both vocalization time and pause time means were significantly longer for the dyslexics on each of the four RAN subtests: objects, colors, numbers, letters. The Gould and Boies analysis showed very little preparation time during speech in both groups, attributing virtually all coding time to pauses, although reanalysis suggested somewhat less. Increased vowel length among the dyslexics occurred on all subtests, but was not maximized on subtests with more numerous postvocalic consonants. Vowel time differences between groups accounted for nearly all of the differences in vocalization time. Profiles were constructed on speech measures which, for each subtest, correctly identified each subject with his group. On the letters subtest it was found that vowel duration alone achieved a perfect discrimination between the dyslexic and control subjects.

The influence of postvocalic consonants on the duration of Spanish vowels

The present work was undertaken in order to provide further evidence about the role played by the physiological and phonological factors in vowel lengthening before voiced consonants. Previous experiments compared cross‐linguistically different consonantal contexts and syllabic types, but, with respect to Spanish disregarded neutralization in final syllable position. Two male adults recorded nonsense bisyllabic words and two other speakers recorded meaningful frequent words where the opposition voiced/voiceless was spontaneously neutralized. Results showed that in open and closed syllables of nonsense utterances (average ratios: 1.4 and 1.23, respectively) vowels are shorter before voiceless consonants than before voiced. In meaningful words, vowels presented longer duration before voiced realizations (20%) of lengthening. However, for nonsense utterances, higher values were obtained and we can assume that this difference is indicating some phonological effect. The lengthening value observed in meaningful words seems to represent more closely the physiological effect.

Consonant/vowel ratio: an improbable cue in speech.

The idea of the consonant duration relative to the vowel duration as a cue to voicing of postvocalic consonants is almost three decades old. Port and Dalby (1982) offer what they believeto be convincing support for such a view. We argue that the acceptance of this idea is premature and probably incorrect. In every instance that the concept of consonant! vowel (C/V) ratio is contrasted with an alternative view, the latter provides a significantly better description of the results. This alternative view considers consonant and vowel duration as independent cues to voicing, following the evaluation and integration of cues within the fuzzy-logical model of speech perception (Massaro & Cohen, 1976, 1977;' Massaro & Oden, 1980a, 1980b;Oden & Massaro, 1978). The first relevant study was carried out by Denes (1955), who varied vowel duration and the final consonant duration in the perception of the voicing difference between the pronunciations of the word use. Without any formal analysis, Denes interpreted the results in terms of the ratio of consonant duration to vowel duration, serving as a cue to voicing of the final consonant. The perceived voicing should decrease systematically with increases in the C/V ratio. However, in an earlier paper (Massaro & Cohen, 1977), we provided a quantitative test of the C/V ratio hypothesis against the observed results of Denes (1955). We also tested the idea that vowel duration and consonant duration provide independent cues to voicing of the consonant. The fit of the latter model was twice as good as that of the former, even though the better model required only three-fifths as many free parameters. In the present note, we evaluate the C/V ratio model against the data of Derr and Massaro (1980) and Port and Dalby (1982). The present tests offer as much flexibility as possible for the quantification of the C/V ratio idea. In addition, we contrast the C/V ratio model against the predictions of the fuzzylogical model, assuming independent vowel and consonant duration cues. The fuzzy-logicalmodel does a

Fundamental frequency as a cue to postvocalic consonantal voicing: some data from speech perception and production.

Several recent studies by Lehiste have reported that changes in fundamental frequency (F0) can serve as a cue to perceived vowel length and, furthermore, that the perceived lengthening of the vowel can influence perception of the voicing feature of stop consonants in syllable-final position. In Experiment 1, we replicated Lehiste’s basic results for stop consonants in final position. Experiment 2 extended these results to postvocalic fricatives. The final consonant in syllables of intermediate vowel duration was more often perceived as voiced when F0 was falling than when F0 was monotone. In Experiment 3, we examined the F0 contours produced by eight talkers before postvocalic stop consonants and fricatives in natural speech for minimal pairs of words differing in voicing. The amount of change of F0 over the vowel was no greater before voiced than voiceless consonants, suggesting that the earlier perceptual effects cannot be explained by appealing to regularities observed in the production of F0 contours in vowels preceding postvocalic consonants.

Fundamental frequency as a cue to postvocalic consonant voicing in production: Developmental data

Several studies by Lehiste have indicated that fundamental frequency (F0) contour affects perception of vowel length and of postvocalic consonant voicing; however, recent evidence from speech production showed no such relationship between F0 contour and voicing of postvocalic consonants [T. M. Gruenenfelder, J. Acoust. Soc. Am. Suppl. 1 65, S8(A) (1979)]. The present study was designed to investigate F0 contours in relation to postvocalic consonant voicing in speech production from a developmental perspective. The experimental stimuli consisted of three minimal word pairs, which differed in the voicing feature of the postvocalic stop consonant. Subjects. as young as three years of age and with normal language and articulation skills and normal heating sensitivity, named the stimuli in single word productions. The F0 at the start of the vowel (F0s), F0 at the end of the vowel (F0e), and the change in F0 (ΔF0 = F0s − F0e) were calculated for each trial of all six stimuli for each speaker. Findings will be discussed with regard to the voicing feature of the postvocalic consonant, the minimal word pairs studied, and subject age. [Work supported by NIH.]

Influence of Postvocalic Consonants on Vowel Duration in Esophageal Speech

The durations of vowels preceding voiced-voiceless stops in utterances produced by three esophageal speakers and three normal speakers were measured. Vowels were significantly longer before voiced stops than before voiceless stops for both esophageal and normal speakers. For either postvocalic consonant environment, the average absolute durations of the vowels of the esophageal speakers were longer than those of the normal speakers. Speaker-group comparisons revealed no significant difference in vowel duration preceding voiceless stops; however, the average absolute duration of vowels preceding voiced stops was significantly longer for the esophageal group. Speaker-group comparisons revealed no significant differences in the relative differences in vowel duration preceding voiced-voiceless stops. The data were interpreted to support the view that the vowel length variation observed is a language-specific behavior governed by a phonological rule of the English language, rather than simply a language-universal behavior governed by inherent physiological characteristics of the speech-production mechanism. Moreover, it was suggested that this phonological rule is a lengthening rule, which lengthens vowels before voiced consonants, rather than a shortening rule, which shortens vowels before voiceless consonants.

A strategy for the interpretation of durational cues in spoken sentences

A perceptual strategy will be proposed for interpreting durational cues to (1) the identity of segments, (2) the stress pattern, and (3) aspects of the syntactic structure of spoken utterance. Since segmental durations are influenced by many factors, knowledge of the appropriate rules concerning the phonological and durational patterns of words and word sequences must be precompiled into a decoding network of expected segmental durations. During the processing of an unknown utterance, some deviations from durational expectations provide cues to syntactic structure, while other discrepancies are used to penalize the matching score for a word. For example, if a content word has a longer-than-usual final syllable (including both the vocal and any postvocalic consonants) in English, the end of a constituent phrase or clause is suggested. On the other hand, shorter-than-usual content words are likely to function as the first elements of compounds. [Research supported by the National Institutes of Health.]

An acoustic correlate of the force of articulation

Although the force of articulation is a familiar concept in phonetics, the phenomenon is not easily described. As a result, it was questioned as such a few years ago. It is generally accepted that the duration of the preconsonantal vowel determines the distinction between fortis and lenis. For obvious reasons, this is quite irrelevant for initial consonants. A significant number of measurements concerning stops and fricatives in nonsense words as recorded by W. A. Smalley, for example, and samples from Korean, French and Dutch have demonstrated that the rise time of the postconsonantal vowel and the decay time of the preconsonantal vowel are inversely proportionate to the force of articulation. It follows that this relation can be considered an acoustic correlate of the force of articulation. Since it determines both prevocalic and postvocalic consonants, this correlate may be regarded as more economical than the one that was previously established.

Linguistic uses of segmental duration in English: acoustic and perceptual evidence.

The pattern of durations of individual phonetic segments and pauses conveys information about the linguistic content of an utterance. Acoustic measures of segmental timing have been used by many investigators to determine the variables that influence the durational structure of a sentence. The literature on segmental duration is reviewed and related to perceptual data on the discrimination of duration and to psychophysical data on the ability of listeners to make linguistic decisions on the basis of durational cues alone. We conclude that, in English, duration often serves as a primary perceptual cue in the distinctions between (1) inherently long verses short vowels, (2) voiced verses voiceless fricatives, (3) phrase-final verses non-final syllables, (4) voiced versus voiceless postvocalic consonants, as indicated by changes to the duration of the preceding vowel in phrase-final positions, (5) stressed verses unstressed or reduced vowels, and (6) the presence or absence of emphasis. Subject Classification: [43]70.40, [43]70.70, [43]70.20.

Preliminary Investigation of the Acoustical Characteristics of Inter-Phonemic Transitions

The study employed selected vowels, each combined with prevocalic or post-vocalic consonants in consonant-vowel or vowel-consonant syllables. Each combination was recorded non-contextually by several speakers and then tested by listeners for recognizability of phonemes. Oscillograms and sound spectrograms were made of all syllables correctly identified. These were used to obtain several measures of syllabic component duration and formant frequency change during transition. Measures of direction and extent of frequency change during transitions appeared to offer most promise of relationship to known physiological features of articulation and were subjected to more complete analysis. Results of the study indicate the following: (1) for the first two formants, the transitions reflect aspects of tongue placement for the vowel, and place and manner of articulation and voicing characteristics of the consonant; (2) lack of speaker agreement resulted in variations obscuring most aspects of patterning for the third formant. Specific hypotheses were tested within the limits of the experimental procedure and results are reported. Future research trends are suggested.