Changes In Vowel Duration Research Articles

The development of cortical processing of speech differs between children with cochlear implants and normal hearing and changes with parental singing.

The aim of the present study was to investigate speech processing development in children with normal hearing (NH) and cochlear implants (CI) groups using a multifeature event-related potential (ERP) paradigm. Singing is associated to enhanced attention and speech perception. Therefore, its connection to ERPs was investigated in the CI group. The paradigm included five change types in a pseudoword: two easy- (duration, gap) and three difficult-to-detect (vowel, pitch, intensity) with CIs. The positive mismatch responses (pMMR), mismatch negativity (MMN), P3a and late differentiating negativity (LDN) responses of preschoolers (below 6 years 9 months) and schoolchildren (above 6 years 9 months) with NH or CIs at two time points (T1, T2) were investigated with Linear Mixed Modeling (LMM). For the CI group, the association of singing at home and ERP development was modeled with LMM. Overall, responses elicited by the easy- and difficult to detect changes differed between the CI and NH groups. Compared to the NH group, the CI group had smaller MMNs to vowel duration changes and gaps, larger P3a responses to gaps, and larger pMMRs and smaller LDNs to vowel identity changes. Preschoolers had smaller P3a responses and larger LDNs to gaps, and larger pMMRs to vowel identity changes than schoolchildren. In addition, the pMMRs to gaps increased from T1 to T2 in preschoolers. More parental singing in the CI group was associated with increasing pMMR and less parental singing with decreasing P3a amplitudes from T1 to T2. The multifeature paradigm is suitable for assessing cortical speech processing development in children. In children with CIs, cortical discrimination is often reflected in pMMR and P3a responses, and in MMN and LDN responses in children with NH. Moreover, the cortical speech discrimination of children with CIs develops late, and over time and age, their speech sound change processing changes as does the processing of children with NH. Importantly, multisensory activities such as parental singing can lead to improvement in the discrimination and attention shifting toward speech changes in children with CIs. These novel results should be taken into account in future research and rehabilitation.

Effects of an intensive voice treatment on articulatory function and speech intelligibility in children with motor speech disorders: A phase one study

Producing speech that is clear, audible, and intelligible to others is a challenge for many children with cerebral palsy (CP) and children with Down syndrome (DS). Previous studies have demonstrated the effectiveness of using the Lee Silverman Voice Treatment (LSVT LOUD®) to increase vocal loudness and improve speech intelligibility in individuals with dysarthria secondary to Parkinson’s disease (PD), and some research suggests that it also may be effective for individuals with dysarthria secondary to other conditions, including CP and DS. Although LSVT LOUD targets healthy vocal loudness, there is some evidence of spreading effects to the articulatory system. Acoustic data from two groups of children with secondary motor speech disorders [one with CP (n = 17) and one with DS (n = 9)] who received a full dose of LSVT LOUD and for whom post-treatment intelligibility gains have been previously reported, were analyzed for treatment effects on: 1) vowel duration, 2) acoustic vowel space and 3) the ratio of F2/i/ to F2/u/. Statistically significant changes in vowel duration and acoustic vowel space occurred pre-treatment to 12 weeks post-treatment in the CP group, and increased acoustic vowel space was observed in 5 of the DS participants. The present study provides preliminary evidence of intensive voice treatment spreading effects to the articulatory system in some children with CP and children with DS consistent with previous findings in other populations.

Standardized low-resolution electromagnetic tomography of preattentive auditory discrimination in accumulative drinker

Background: The present study proposes a task-dependent hypothesis in which the phonological units of segmental (e.g., consonant and vowel) and suprasegmental (e.g., prosodic) are processed in discrete asymmetry of the human brain. Although the left hemisphere (LH) is selectively employed for processing linguistic information irrespectively of acoustic cues or subtype of phonological unit, the right hemisphere (RH) is employed for prosody-specific cues.Although the left hemisphere is selectively employed for processing linguistic information irrespectively of acoustic cues or subtype of phonological unit, the right hemisphere is employed for prosody-specific cues.
 Aims and Objective: As both hemispheres are lateralized for speech and language, the objective of this study is to extend the investigation of how the pre-attentive processing of vowel duration changes of Thai monosyllabic words in alcoholic drinkers.
 Materials and Methods: Forty healthy right-handed adults participated in this study.
 Results: This study found that both rising-to-falling and falling-to-rising tone changes perception elicited MMN between 245-297 msec with reference to the standardstimulus ERPs. The long-to-short and short-to-long vowel duration changes elicited a strong MMN for both groups. Source localization was obtained in the Middle Temporal Gyrus (MTG) of the left hemisphere (LH) for both groups.
 Conclusion: Automatic detection of changes in contour tones is a useful index of language universal auditory memory traces.

Twenty-eight years of vowels: Tracking phonetic variation through young to middle age adulthood

Research on age-related changes in speech has primarily focused on comparing “young” vs. “elderly” adults. Yet, listeners are able to guess talker age more accurately than a binary distinction would imply, suggesting that acoustic characteristics of speech change continually and gradually throughout adulthood. We describe acoustic properties of vowels produced by eleven talkers based on naturalistic speech samples spanning a period of 28 years, from ages 21 to 49. We find that the position of vowels in F1/F2 space shifts towards the periphery with increasing talker age. Based on Generalized Additive Mixed Effects models, we show that this shift is not fully attributable to changes in vowel duration or to segmental context. We discuss the implications of our results for research on aging and speech, and for research in which durational shortening and spectral characteristics of vowels are assumed to reflect a unitary process of phonetic reduction.

Noise Equally Degrades Central Auditory Processing in 2- and 4-Year-Old Children.

The aim of this study was to investigate developmental and noise-induced changes in central auditory processing indexed by event-related potentials in typically developing children. P1, N2, and N4 responses as well as mismatch negativities (MMNs) were recorded for standard syllables and consonants, frequency, intensity, vowel, and vowel duration changes in silent and noisy conditions in the same 14 children at the ages of 2 and 4 years. The P1 and N2 latencies decreased and the N2, N4, and MMN amplitudes increased with development of the children. The amplitude changes were strongest at frontal electrodes. At both ages, background noise decreased the P1 amplitude, increased the N2 amplitude, and shortened the N4 latency. The noise-induced amplitude changes of P1, N2, and N4 were strongest frontally. Furthermore, background noise degraded the MMN. At both ages, MMN was significantly elicited only by the consonant change, and at the age of 4 years, also by the vowel duration change during noise. Developmental changes indexing maturation of central auditory processing were found from every response studied. Noise degraded sound encoding and echoic memory and impaired auditory discrimination at both ages. The older children were as vulnerable to the impact of noise as the younger children. https://doi.org/10.23641/asha.5233939.

Neural Processes Associated with Vocabulary and Vowel-Length Differences in a Dialect: An ERP Study in Pre-literate Children.

Although familiarity with a language impacts how phonology and semantics are processed at the neural level, little is known how these processes are affected by familiarity with a dialect. By measuring event-related potentials (ERPs) in kindergarten children we investigated neural processing related to familiarity with dialect-specific pronunciation and lexicality of spoken words before literacy acquisition in school. Children speaking one of two German dialects were presented with spoken word-picture pairings, in which congruity (or the lack thereof) was defined by dialect familiarity with pronunciation or vocabulary. In a dialect-independent control contrast, congruity was defined by audio-visual semantic (mis)match. Congruity effects and congruity-by-dialect group interactions in the ERPs were tested by data-driven topographic analyses of variance (TANOVA) and theory-driven focal analyses. Converging results revealed similar congruity effects in the N400 and late-positive-complex (LPC) in the control contrast for both dialect groups. In the dialect-specific vocabulary contrast, topographies of the N400- and LPC-effects were reversed depending on familiarity with the presented dialect words. In the dialect-specific pronunciation contrast, again a topography reversal was found depending on dialect familiarity, however, only for the LPC. Our data suggest that neural processing of unfamiliar words, but not pronunciation variants, is characterized by semantic processing (increased N400-effect). However, both unfamiliar words and pronunciation variants seem to engage congruity judgment, as indicated by the LPC-effect. Thus, semantic processing of pronunciation in dialect words seems to be rather robust against slight alterations in pronunciation, like changes in vowel duration, while such alterations may still trigger subsequent control processes.

Background Noise Degrades Central Auditory Processing in Toddlers.

Noise, as an unwanted sound, has become one of modern society's environmental conundrums, and many children are exposed to higher noise levels than previously assumed. However, the effects of background noise on central auditory processing of toddlers, who are still acquiring language skills, have so far not been determined. The authors evaluated the effects of background noise on toddlers' speech-sound processing by recording event-related brain potentials. The hypothesis was that background noise modulates neural speech-sound encoding and degrades speech-sound discrimination. Obligatory P1 and N2 responses for standard syllables and the mismatch negativity (MMN) response for five different syllable deviants presented in a linguistic multifeature paradigm were recorded in silent and background noise conditions. The participants were 18 typically developing 22- to 26-month-old monolingual children with healthy ears. The results showed that the P1 amplitude was smaller and the N2 amplitude larger in the noisy conditions compared with the silent conditions. In the noisy condition, the MMN was absent for the intensity and vowel changes and diminished for the consonant, frequency, and vowel duration changes embedded in speech syllables. Furthermore, the frontal MMN component was attenuated in the noisy condition. However, noise had no effect on P1, N2, or MMN latencies. The results from this study suggest multiple effects of background noise on the central auditory processing of toddlers. It modulates the early stages of sound encoding and dampens neural discrimination vital for accurate speech perception. These results imply that speech processing of toddlers, who may spend long periods of daytime in noisy conditions, is vulnerable to background noise. In noisy conditions, toddlers' neural representations of some speech sounds might be weakened. Thus, special attention should be paid to acoustic conditions and background noise levels in children's daily environments, like day-care centers, to ensure a propitious setting for linguistic development. In addition, the evaluation and improvement of daily listening conditions should be an ordinary part of clinical intervention of children with linguistic problems.

Pre-attentive sensitivity to vowel duration reveals native phonology and predicts learning of second-language sounds

In some languages (e.g. Czech), changes in vowel duration affect word meaning, while in others (e.g. Spanish) they do not. Yet for other languages (e.g. Dutch), the linguistic role of vowel duration remains unclear. To reveal whether Dutch represents vowel length in its phonology, we compared auditory pre-attentive duration processing in native and non-native vowels across Dutch, Czech, and Spanish. Dutch duration sensitivity patterned with Czech but was larger than Spanish in the native vowel, while it was smaller than Czech and Spanish in the non-native vowel. An interpretation of these findings suggests that in Dutch, duration is used phonemically but it might be relevant for the identity of certain native vowels only. Furthermore, the finding that Spanish listeners are more sensitive to duration in non-native than in native vowels indicates that a lack of duration differences in one’s native language could be beneficial for second-language learning.

Fast parametric evaluation of central speech-sound processing with mismatch negativity (MMN)

The aim of this study was to develop a paradigm for obtaining a multi-feature profile for central auditory processing of different magnitudes of prosodic and phonetic changes in speech sounds. We recorded the MMNs to three vowel identity changes, three magnitudes of changes in intensity, and vowel duration as well as to two magnitudes of pitch changes from semi-synthetic vowels in 34min. Furthermore, we examined how the type and magnitude of deviation affect the size and timing of the MMN. All sound changes elicited statistically significant MMN responses, with the MMN amplitudes increasing with an increase in sound deviance. Importantly, the MMN amplitudes for the vowel changes reflected the differences between the phonemes, as did the MMNs to vowel-duration changes reflect the categorization of these sounds to short and long vowel categories, which are meaningful in the Finnish language. This new multi-feature MMN paradigm is suitable for investigating the central auditory processing of different magnitudes of speech-sound changes and can be used, for instance, in the investigation of pre-attentive phoneme categorization. The paradigm is especially useful for studying speech and language disorders in general, language development, and evolution of phoneme categories early in life, as well as brain plasticity during native or second language learning.

Source Localization of Preattentive Processing for Different Vowel Duration Changes with Contour Tones in Monosyllabic Thai Words

Source Localization of Preattentive Processing for Different Vowel Duration Changes with Contour Tones in Monosyllabic Thai Words

Preattentive Processing of Different Vowel Duration Changes with Level Tones in Monosyllabic Thai Words

Preattentive Processing of Different Vowel Duration Changes with Level Tones in Monosyllabic Thai Words

Linguistic multifeature MMN paradigm for extensive recording of auditory discrimination profiles

We studied whether a multifeature mismatch negativity (MMN) paradigm using naturally produced speech stimuli is feasible for studies of auditory discrimination accuracy of adult participants. A naturally produced trisyllabic pseudoword was used in the paradigm, and MMNs were recorded to changes that were acoustic (changes in fundamental frequency or intensity) or potentially phonological (changes in vowel identity or vowel duration). All the different changes were presented in three different word segments (initial, middle, or final syllable). All changes elicited an MMN response, but the vowel duration change elicited a different response pattern than the other deviant types. Changes in vowel duration and identity also had an effect on MMN lateralization. Our results show that assessing speech sound discrimination of several features in word context is possible in a short recording time (30 min) with the multifeature paradigm.

Dutch and English listeners’ interpretation of vowel duration

Dutch and English listeners' interpretation of vowel duration changes was examined in a word transcription task. Listeners were presented with spoken words realized with canonical or altered vowel durations. Dutch listeners often misperceived lengthened short vowels and shortened long vowels, identifying them as the short/long counterpart of the target, whereas English listeners more rarely misidentified words with altered vowel duration. Although Dutch and English are similar prosodically and phonologically, listeners' treatment of vowel duration in clear speech is different across the two languages.

Modulation of the mismatch negativity (MMN) to vowel duration changes in native speakers of Finnish and German as a result of language experience

While crucial for phoneme distinctions in the Finnish language, mere vowel duration is of lower relevance as a phonetically distinctive cue in the German language. To investigate the pre-attentive processing of vowel duration between these two languages, the mismatch negativity (MMN), a component of the auditory event-related potential (ERP) that is an index of automatic auditory change detection, was measured in Finnish and German native speakers for vowel duration changes embedded in the pseudoword sasa. Vowel duration changes thereby were presented as a shortening or a lengthening of either the first- or second-syllable vowel. An additional non-speech condition measured the MMN to duration and frequency changes in tones. In both language groups, diminished MMN amplitudes for the shortening of vowel duration in the word-final syllable suggested a generally more difficult discrimination of vowel duration in a word-final position. Further, shorter MMN latencies for the Finns than the Germans for vowel duration as well as tone duration deviants suggested a generally higher sensitivity to duration contrasts in the Finnish language group. No latency difference between the groups was found for tone frequency processing. Moreover, the Finns, but not the Germans, showed a leftward shift of the MMN scalp distribution for changes in vowel duration, whereas the MMN topography was highly similar between both groups in the tone condition. An enhanced phonetic processing of vowel duration changes and possibly an enhanced processing of sound duration in general is thus indicated for the Finns as a result of their extensive linguistic experience with phonetically distinctive vowel duration contrasts in the native language.

Kinematics of compensatory vowel shortening: the effect of speaking rate and coda composition on intra- and inter-articulatory timing

The acoustic shortening of vowels has been demonstrated to occur across a variety of contextual variations, including speaking rate and coda composition (i.e., singleton consonant vs. consonant cluster). The current study examined two possible types of kinematic adjustments which may account for changes in vowel duration. Results indicated that increased speaking rates were effected by changes primarily in the dynamic specification of the jaw opening gesture, but may also have occurred in combination with increased articulatory overlap of the vowel by the successive consonant(s). Consonant cluster productions appeared to be effected solely by increased articulatory overlap, with these kinematic adjustments being maintained across the different speaking rates. As the timing of the jaw closing onset shifted earlier for cluster productions, the relative timing of the upper lip and jaw did not remain invariant. Substantial intersubject variation was observed in the implementation of these kinematic strategies. These findings suggest that, in order to achieve the intended acoustic-perceptual goals, both intra- and inter-articulatory timing may not be absolutely invariant, but rather, systematically and individually organized across task manipulations.

An Articulatory Study of Consonant-Induced Vowel Duration Changes in English

The effects of voicing, manner, and number of consonants on the duration of previous vowels in English can be created in three ways: by planned expansion or contraction of the entire vowel, by changing the relative timing of consonant and vowel gestures, or by modifying the duration of the closing movement for the consonants. An X-ray microbeam data base of 2 speakers of American English reciting monosyllabic words, which differed in their final consonants and in their position in the accentual structure of the utterance, was studied to evaluate these three accounts. In this data base, vowel duration differences due to the voicing of the following consonants were amplified by the presence of accent. Also, many of the duration differences associated with the following consonants are localized in the later portion of the opening movement, suggesting that subjects often create vowel duration changes by initiating the consonant closing gesture at an earlier or later time relative to the opening gesture.

The articulation of consonant-induced vowel duration changes in English

This reports on an articulatory investigation of acoustic findings that vowels tend to be longer before voiced than voiceless consonants [House and Fairbanks, J. Acoust. Soc. Am. (1953)], before fricatives than stops [Umeda, J. Acoust. Soc. Am. (1975)], and before single consonants than before multiple consonants [Fowler, J. Exp. Psychol. (1983)]. Measurements were taken from tongue movement traces obtained with the Wisconsin microbeam system during vowels in accented and unaccented conditions. Assuming a gestural theory of speech production, three mechanisms for producing these duration differences are considered: The duration of the closing gesture may be stretched, the consonantal gesture may begin later in the vowel, or the production of the entire vowel may be lengthened. One subject's vowel durations were affected by the voicing and manner of the following consonant. Another's were affected only by consonant voicing when the word is accented, and only by consonant duration when the word is unaccented. Moreover, the effect of duration and voicing on the vowel duration was due, in part, to differences in how early the closing gesture for the consonant begins, while the effect of manner of articulation was due entirely to differences in the duration of the closing gesture. [Work supported, in part, by NSF.]

Effects of stress and final-consonant voicing on vowel production: articulatory and acoustic analyses.

Durations of the vocalic portions of speech are influenced by a large number of linguistic and nonlinguistic factors (e.g., stress and speaking rate). However, each factor affecting vowel duration may influence articulation in a unique manner. The present study examined the effects of stress and final-consonant voicing on the detailed structure of articulatory and acoustic patterns in consonant-vowel-consonant (CVC) utterances. Jaw movement trajectories and F 1 trajectories were examined for a corpus of utterances differing in stress and final-consonant voicing. Jaw lowering and raising gestures were more rapid, longer in duration, and spatially more extensive for stressed versus unstressed utterances. At the acoustic level, stressed utterances showed more rapid initial F 1 transitions and more extreme F 1 steady-state frequencies than unstressed utterances. In contrast to the results obtained in the analysis of stress, decreases in vowel duration due to devoicing did not result in a reduction in the velocity or spatial extent of the articulatory gestures. Similarly, at the acoustic level, the reductions in formant transition slopes and steady-state frequencies demonstrated by the shorter, unstressed utterances did not occur for the shorter, voiceless utterances. The results demonstrate that stress-related and voicing-related changes in vowel duration are accomplished by separate and distinct changes in speech production with observable consequences at both the articulatory and acoustic levels.

Effects of bite block speech on intrinsic segment duration.

The fact that low vowels tend to have longer intrinsic duration than high vowels is sometimes attributed to mechanical characteristics associated with the greater distance the jaw travels in producing low vowels. To investigate this tendency, 6 adult speakers of English each produced 72 [h]-vowel-consonant stimuli containing high and low vowels under 'normal' conditions and with their jaw fixed. If duration differences commonly observed between high and low vowels are a result of only mechanical effects of mandibular movement, it was hypothesized that stabilizing the jaw would eliminate these intrinsic vowel duration differences. Based on acoustic measurements that were made, it was found that the fixed-jaw conditions affected the intrinsic durational differences between high and low vowels to some extent, but the contrast was not entirely removed. In addition to the vowel duration changes, a number of systematic effects upon consonant closure duration were also observed as a result of the normal versus fixed-jaw conditions.

Effects of speaking rate on the perception of syllable-initial stop consonants

It has been shown that the effect of speaking rate on the perception of voice onset time (VOT) is strongest in the immediate vicinity of the target stop consonant: Listeners interpret a given VOT value in accordance with the duration of the CV syllable containing the stop consonant [A. Q. Summerfield, J. Exp. Psychol. Human Percept. Perform. 7, 1074–1095 (1981); J. L. Miller et al., J. Acoust. Soc. Am. Suppl. 1 76, S89 (1984)]. These studies used stimuli that are unlikely to occur in natural speech. The first study used simplified synthetic VOT continua; the second study used computer-edited natural-speech VOT continua, but in which syllable duration was kept constant, so that vowel duration decreased as VOT increased. The present study explored the effects of speaking rate on the perception of syllable-initial stop consonants in more natural circumstances. Natural-speech [bi-pi] continua were constructed, in which vowel rather than syllable duration was kept constant. Preliminary results indicate that the phoneme boundary is not, or only minimally, affected by changes in vowel duration.