Showing papers on "Voice published in 1985"

Contextual effects on vowel duration, closure duration, and the consonant/vowel ratio in speech production

Abstract: Acoustic measurements were conducted to determine the degree to which vowel duration, closure duration, and their ratio distinguish voicing of word‐final stop consonants across variations in sentential and phonetic environments. Subjects read CVC test words containing three different vowels and ending in stops of three different places of articulation. The test words were produced either in nonphrase‐final or phrase‐final position and in several local phonetic environments within each of these sentence positions. Our measurements revealed that vowel duration most consistently distinguished voicing categories for the test words. Closure duration failed to consistently distinguish voicing categories across the contextual variables manipulated, as did the ratio of closure and vowel duration. Our results suggest that vowel duration is the most reliable correlate of voicing for word‐final stops in connected speech.

How the young French child avoids the pre-voicing problem for word-initial voiced stops.

Abstract: Macken & Barton (1980) noted an asymmetry in their young Spanish-learning children's word-initial stop productions, as compared with English-learning children's, namely, ‘the Spanish-learning children acquire “lead” voicing…after age four’, whereas ‘English-learning children acquire “long lag” stops…by about 2;6’. ‘One possible explanation’, they propose, ‘is that lead voicing is inherently difficult to produce or at least more difficult to learn than long lag…’. The purpose of this Note is to present data suggesting that young children learning French, which also employs phonetically pre-voiced stops for its phonemically voiced category, also show an asymmetry in their word-initial stop productions. Furthermore, this asymmetry supports the notion, proposed by Macken & Barton, that lead voicing is somehow ‘more difficult’ for these young children to learn to produce. However, the actual ‘strategy’ used by the French-learning children to circumvent this presumed difficulty is different from that used by Macken & Barton's Spanish-learning children. This difference supports the notion that children have a certain degree of latitude in finding their way through the maze of psycholinguistic development (Kiparsky & Menn 1977).

Onset of voicing in stuttered and fluent utterances.

Abstract: Electroglottographic (EGG) and acoustic waveforms of the first few glottal pulses of voicing were monitored and voice onset time (VOT) measured during an adaptation task performed by stutterers and...

Fundamental frequency correlates of stop consonant voicing and vowel quality in the speech of preadolescent children

Abstract: Fundamental frequency (F0) and voice onset time (VOT) were measured in utterances containing voiceless aspirated [ph, th, kh], voiceless unaspirated [sp, st, sk], and voiced [b, d, g] stop consonants produced in the context of [i, e, u, o, a] by 8‐ to 9‐year‐old subjects. The results revealed that VOT reliably differentiated voiceless aspirated from voiceless unaspirated and voiced stops, whereas F0 significantly contrasted voiced with voiceless aspirated and unaspirated stops, except for the first glottal period, where voiceless unaspirated stops contrasted with the other two categories. Fundamental frequency consistently differentiated vowel height in alveolar and velar stop consonant environments only. In comparing the results of these children and of adults, it was observed that the acoustic correlates of stop consonant voicing and vowel quality were different not only in absolute values, but also in terms of variability. Further analyses suggested that children were more variable in production due to inconsistency in achieving specific targets. The findings also suggest that, of the acoustic correlates of the voicing feature, the primary distinction of VOT is strongly developed by 8–9 years of age, whereas the secondary distinction of F0 is still in an emerging state.

Word‐final devoicing in German and the effects of phonetic and sentential contexts

Abstract: The present study investigated the possible effects that place of articulation of the final stop, the phonetic environment of the target word, and sentential position might have on vowel duration, voicing into closure, and closure duration as acoustic correlates of underlying voicing. The results of the study replicate the findings that word‐final devoicing is non‐neutralizing in German. However, the results also show that the temporal correlates of underlying voicing are different for dental and velar stops and are different for lexical items. Moreover, for the dental stops, vowel duration, and voicing into closure as correlates of underlying voicing are not independent of phonetic or sentential contexts. The overall results suggest that the phonetic rules necessary to implement word‐final stops in German must be sensitive to place of articulation, surrounding phonetic and sentential contexts, and even individual lexical items. [Supported by NIH Training Grant T32 NS‐7134.]

The effect of signal degradation on the status of cues to voicing in utterance‐final stop consonants

Abstract: In several recent studies, spectral acoustic cues (eg, voicing during closure, preclosure transition) have been found to have more influence than temporal acoustic cues (eg, vowel or syllable duration) on perception of the voicing distinction in final stops Earlier studies, mostly using synthetic speech, had found vowel duration to be the primary cue to this distinction The present stimuli were taken from a study in which spectral cues had dominated judgments in quiet listening conditions These stimuli were presented against a high level of background noise (S/N=0) to seven normal adult subjects in a forced choice (eg, BED–BET) format In quiet, the correlation of the percentage of the original vowel remaining after deletion with judgments of the final stop as voiced had been 018 In the noise listening condition the correlation was 094 Syllables with voiced final stops from which 76% of the vowel (all but the final transition) had been deleted were judged voiced (82%) in quiet but voiceless (87%) in noise These results indicate that the temporal cue of vowel duration is more resistant to degradation by noise than are spectral cues, and that vowel duration plays a dominant role only when other cues are unavailable

Perceptual cues to the voiced-voiceless distinction of final fricatives for listeners with impaired or with normal hearing

Abstract: Cues to the voicing distinction for final /f,s,v,z/ were assessed for 24 impaired‐ and 11 normal‐hearing listeners. In base‐line tests the listeners identified the consonants in recorded /dvC/ syllables. To assess the importance of various cues, tests were conducted of the syllables altered by deletion and/or temporal adjustment of segments containing acoustic patterns related to the voicing distinction for the fricatives. The results showed that decreasing the duration of /v/ preceding /v/ or /z/, and lengthening the /v/ preceding /f/ or /s/, considerably reduced the correctness of voicing perception for the hearing‐impaired group, while showing no effect for the normal‐hearing group. For the normals, voicing perception deteriorated for /f/ and /s/ when the frications were deleted from the syllables, and for /v/ and /z/ when the vowel offsets were removed from the syllables with duration‐adjusted vowels and deleted frications. We conclude that some hearing‐impaired listeners rely to a greater extent on vowel duration as a voicing cue than do normal‐hearing listeners.

Acquisition of the English Voicing Contrast By Arab Children

Abstract: Children are typically more proficient than adults in learning the phonetic detail of a second language. The purpose of this study was to investigate the acquisition of the English voicing contrast as cued by voice onset time in syllable-initial position and preconsonantal vowel duration in final position in the speech of children whose native language is Arabic. The children, 24 to 135 months in age, were recorded producing minimal pairs differing in the voicing of consonants. Voice onset time and vowel duration were measured from spectrograms. Children were highly variable in their mastery of the voicing contrast. For this sample, neither age nor experience with English could predict phonetic proficiency.

Segmental speech errors occur earlier in utterance planning than certain phonetic processes

Abstract: If single‐segment speech errors occur when planning segments are represented abstractly (i.e., independent of their immediate context), and contextual adjustments are made by later processes which apply after serial ordering errors have occurred, then these contextual adjustments should reflect the influence of segments which have been introduced by error. An example of such a contextual adjustment is the duration difference in CVC syllables, where the voiced portion of the syllable is longer if the final C is voiced, and shorter if the final C is voiceless. In an error‐elicitation experiment using tongue twisters, ten instances were observed where final consonants exchanged, e.g., “dig duck”→“dick dug,” “pack pig”→“pag pick” etc. When these 20 syllables were compared with correct control utterances produced by the same speakers, 19 showed durations of voicing appropriate to the segment that was introduced by error, and one was equivocal. These results are compatible with the hypothesis that segmental interaction errors occur earlier in production planning than at least some phonetic processes, and that these processes then apply to error segments and correct target segments alike. [This research is supported in part by a grant from the National Institutes of Health.]

Preaspiration in phonological stop contrasts : an instrumental phonetic study

Abstract: This study is an experimental phonetic investigation of phonological voicing oppositions - specifically, those involving preaspiration as found in Icelandic, Scottish Gaelic, and Irish Three main aspects of these oppositions are dealt with - The first involves the production 8f these contrasts Productions by native speakers of the three languages were monitored using techniques including electroaerometry and photoelectric glottography Specific attention is directed to the durational correlates of the opposition, and how these vary across languages and for different phonetic environments, including stress variation The differences and similarities between contrasts which involve preaspiration and those which involve postaspiration are discussed in some detail In considering production aspects of these oppositions, interest focusses also on the laryngeal mechanisms which control voicelessness and aspiration (pre- and post-) Glottographic data presented suggests that the nature and the amplitude of glottal gesture for a voiceless or aspirated stop is very precisely tailored to the prevailing aerodynamic conditions The second aspect considered is that of the historical development of these contrasts Past hypotheses are discussed in some detail, and a more phonetically-based alternative is proposed The general tendencies of change which affect voicing oppositions and which have traditionally been termed lenition processes are also considered Suggestions are made regarding the phonetic motivation of such changes, suggestions based on existing research as well as on certain results of this study Thirdly, the perception of these oppositions is considered Perceptual experiments are repotted using synthetic and computeredited natural speech stimuli In the first instance, these tests bear on specific questions regarding the perception of preaspirated stops, which arise out of the production data in the earlier chapters In addition, the broader question of the perception of voicing contrasts is discussed A serious problem facing the researcher in this area (and in the area oflinguistic contrasts generally) is that of how the simple binary linguistic percept is arrived at from the large number of potentially relevant cues The question arises as to whether there is a single dominant cue or whether voicing detection involves separate monitoring of the various cues which have been postulated in the literature A hypothesis is proposed to the effect that the linguistic percept depends on a judgement regarding the relative ratio of two properties of a larger, Vowel+Consonant unit The multiplicity of postulated cues may be an artifact of an excessively segmental approach; these seemingly disparate cues may be seen instead to be feeding into a cumulative decision based on a syllable-type unit

Homonymy and the Voiced-Voiceless Distinction in the Speech of Children with Specific Language Impairment

Abstract: Two studies are reported in which homonymy in the speech of children with specific language impairment (SLI) was examined. In the first study, the degree of homonymy reflected in the speech of 14 SLI children was found to resemble that seen in the speech of a group of language-matched children with normal language (NL). Within each group there was considerable variation in the degree of homonymy observed. An examination of the sound changes that contributed to the children's use of homonymy suggested that homonyms arising from prevocalic voicing were more frequent in the speech of the NL children. The second study represented a more systematic examination of prevocalic voicing differences between NL and SLI children. Minimal pairs differing only in the voicing feature of the initial consonant were produced by four SLI and four language-matched NL children. The SLI children showed greater ability to distinguish the minimal pairs by means of a voiced-voiceless initial consonant contrast, as measured by voic...

Individual differences and word‐final devoicing in Polish

Abstract: Within phonological theory a fundamental distinction is made between rules that are neutralizing and those that are non‐neutralizing. Recently, experimental research has examined a number of neutralizations and has found that they are, in fact, non‐neutralizing, thereby raising questions about the validity of such a distinction (Dinnsen, 1984). The purpose of this paper is to report the results of an experimental study which investigated the phonetic implementation of word‐final devoicing in Polish. All previous phonological accounts of Polish have characterized this devoicing rule as neutralizing. Fifteen pairs of words (distinguished underlyingly by word‐final voicing) were recorded in two contexts (---- ♯C and ---- ♯V by five native speakers of Polish. Measurements of final consonant closure duration, voicing into closure, and preceding vowel duration were obtained for each subject. The results of this study showed that the underlying voice distinction is phonetically preserved. Moreover, we found variation in the implementation of the voice contrast for individual subjects. These findings are similar to those observed for Catalan which also exhibits non‐neutralized word‐final devoicing. [Supported by a research grant from NIH to Indiana University.]

Aerodynamic and acoustic characteristics of the voicing distinction in electronic larynx speech

Abstract: Speech attributes that depend primarily on laryngeal adjustments in normal speech can also be produced by skilled alaryngeal speakers For example, listeners reliably perceive the consonant voicing distinction in the production of good electronic larynx speakers In most cases, electronic larynx speech is produced with a continuous sound source regardless of the voicing features of consonants Therefore, voicing distinctions are evidently not produced by systematic control of voice timing relative to consonantal closure It has been suggested that electronic larynx speakers use some alternative strategies, such as markedly higher intraoral pressure for voiceless consonants than for their voiced cognates, producing different acoustic patterns for different voicing features In this study, acoustic and intraoral pressure measurements were made during multiple repetitions of nonsense syllables produced by laryngectomees and normals with and without (transcervical‐type) electronic larynges Different aerodyna

Perception of duration of medial silent intervals in speech and nonspeech signals

Abstract: Vowels are longer before voiced consonants than before voiceless consonants, and a number of studies have demonstrated that perception of voicing, in syllable‐final and intervocalic positions, is in accordance with this production regularity. We present a study, using nonspeech stimuli, that suggests that this agreement between production and perception for segmental duration is grounded in auditory processing of complex stimuli in general. Two types of square‐wave analogs, modeled after a speech series ranging from “aba” to “apa” were constructed. The two nonspeech stimulus series varied in duration of a silent interval from 20–110 ms bounded by frequency transitions out of and into steady‐state segments. One series had an initial segment duration of 155 ms, whereas, the initial segment duration of the other series was 245 ms. Duration of the final segment was 188 ms for both series. Listeners judged significantly more of these nonspeech stimuli to be similar to the short silent interval endpoint when the initial segment was long than when the initial segment was short. This result parallels the finding for speech that listeners perceived more voiced /b/ than voiceless /p/ consonants following longer vowels. These results call into question explanations of this production/perception concordance that suggest either mediation of perception by knowledge of production regularities, or direct perception or articulation. [Work supported by NICHHD.]

Perception of word‐final voicing in two sentence contexts

Abstract: Stressed syllables produced before major syntactic boundaries typically exhibit a marked lengthening, suggesting that listeners may have expectations regarding the relative length of syllables occurring immediately before a major syntactic boundary. We investigated the possible consequences of such expectations for the perception of word‐final stop voicing, which may be cued by vowel and/or closure duration. We examined labeling performance for two continua of synthetic stop‐vowel‐stop words varying in vowel and closure duration. These continua were embedded in synthetic, monotone sentences in which the target stimuli occurred either at the end of an initial subordinate clause or one word before a clause boundary. For half of stimuli, a pause occurred at the boundary; for the other half, no pause occurred. Expectation of phrase‐final lengthening produced a large effect on labeling performance, but only when a pause occurred at the clause boundary. The implications of these findings for perception of voicing as a function of syntactic and phonetic context will be discussed. [Supported by NIH grant no. NS‐12179 to Indiana University.]