Spectrographic study of vowel reduction (original) (raw)
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An Acoustic Profile Of Consonant Reduction
1996
Vowel reduction has been studied for years. It is a universal phenomenon that reduces the distinction of vowels in informal speech and unstressed syllables. How consonants behave in situations where vowels are reduced is much less well known. In this paper we compare durational and spectral data (for both intervocalic consonants and vowels) segmented from read speech with otherwise identical segments from spontaneous speech. On a global level, it shows that consonants reduce like vowels when the speaking style becomes informal. On a more detailed level there are differences related to the type of the consonant.
An acoustic description of consonant reduction
Speech Communication, 1999
The acoustic consequences of the articulatory reduction of consonants remain largely unknown. Much more is known about acoustic vowel reduction. Whether the acoustical and perceptual consequences of articulatory consonant reduction are comparable in kind and extent to the consequences of vowel reduction is still an open question. In this study we compare acoustic data for 791 VCV realizations, containing 17 Dutch intervocalic consonants and 13 vowels, extracted from read speech from a single male speaker, to otherwise identical segments isolated from spontaneous speech. Five acoustic correlates of reduction were studied. Acoustic tracers of articulation were based on F 2 slope dierences and locus equations. Speech eort was assessed by measuring duration, spectral balance, and the intervocalic sound energy dierence of consonants. On a global level, it shows that consonants reduce acoustically like vowels on all investigated accounts when the speaking style becomes informal or syllables become unstressed. Methods that are sensitive to speech eort proved to be more reliable indicators of reduction than F 2 based measures. On a more detailed level there are dierences related to the type of consonant. The acoustic results suggest that articulatory reduction will decrease the intelligibility of consonants and vowels in comparable ways.
NOVEL MEASURES FOR VOWEL REDUCTION
Proceedings of the 16th International Congress of …, 2007
Novel measures for vowel reduction are presented here, for examining vowel space as a whole, and for quantifying reduction of individual vowels. These measures were used to evaluate the degree of vowel reduction in continuous speech, as manifested in the F1-F2 plane. The new measures were applied to a set of 1500 tokens, extracted from a database of spontaneous Hebrew speech (30 tokens of each vowel, recorded from five men and five women). Using a similarity measure, we found that vowels were reduced by a factor of 2.09 for men and by 2.93 for women. The reduced vowel space for men was more distorted than for women. Error measure estimations were larger for men in comparison to women (0.0714 versus 0.0525, respectively). While vowel reduction in women exhibited a relatively symmetric pattern across vowels, it showed a skewed pattern in men. This was attributed to a more pronounced reduction in the back vowels /o/ and /u/.
Acoustic and articulatory manifestations of vowel reduction in German
Journal of the International Phonetic Association, 2008
Recent phonological approaches incorporate phonetic principles in the motivation of phonological regularities, e.g. vowel reduction and neutralization in unstressed position by target undershoot. So far, evidence for this hypothesis is based on impressionistic and acoustic data but not on articulatory data. The major goal of this study is to compare formant spaces and lingual positions during the production of German vowels for combined effects of stress, accent and corrective contrast. In order to identify strategies for vowel reduction independent of speaker-specific vocal-tract anatomies and individual biomechanical properties, an approach similar to the Generalized Procrustes Analysis was applied to formant spaces and lingual vowel target positions. The data basis consists of the German stressed and unstressed full vowels /i… I y… Y e… E E… P… { a… a o… O u… U/ from seven speakers recorded by means of electromagnetic midsagittal articulography (EMMA). Speaker normalized articulatory and formant spaces gave evidence for a greater degree of coarticulation with the consonant context for unstressed vowels as compared to stressed vowels. However, only for tense vowels could spatial reduction patterns be attributed to vowel shortening, whereas lax vowels were reduced without shortening. The results are discussed in the light of current theories of vowel reduction, i.e. target undershoot, Adaptive Dispersion Theory and Prominence Alignment.
Towards a gradual scale of vowel reduction: a pilot study
The study reports the results of an acoustic analysis of vowel reduction of the /iː/ vowel, considering all three traditionally explored aspects of vowel reduction, i.e. duration, F1 and F2 in read speech produced by 12 native speakers of English. Starting from the observation that the standard literature considers only duration as a proxy for overall reduction, the aim of the study is to verify whether duration, F1 and F2 exhibit reduction (construed as shortening of duration and centralization of formants, respectively) to the same degree. The r test reveals the lack of a robust linear correlation between duration, F1 and F2, the highest value being 0.51 (the correlation between duration and F1) and 0.24 (the correlation between duration and F2), neither of which is a strong correlation. In light of the results, the study seeks to establish a gradual scale of vowel reduction, combining the spatial and the temporal aspects by means of averaging the distances between the least and the most reduced tokens across duration, F1/F2 on an equal basis. The resulting degree is expressed on a scale of reduction, ranging from 0 (no reduction whatsoever) to 100 per cent (reduction to schwa).
Effect of vocal effort on spectral properties of vowels
Journal of The Acoustical Society of America, 1999
The effects of variations in vocal effort corresponding to common conversation situations on spectral properties of vowels were investigated. A database in which three degrees of vocal effort were suggested to the speakers by varying the distance to their interlocutor in three steps ͑close-0.4 m, normal-1.5 m, and far-6 m͒ was recorded. The speech materials consisted of isolated French vowels, uttered by ten naive speakers in a quiet furnished room. Manual measurements of fundamental frequency F0, frequencies, and amplitudes of the first three formants (F1, F2, F3, A1, A2, and A3͒, and on total amplitude were carried out. The speech materials were perceptually validated in three respects: identity of the vowel, gender of the speaker, and vocal effort. Results indicated that the speech materials were appropriate for the study. Acoustic analysis showed that F0 and F1 were highly correlated with vocal effort and varied at rates close to 5 Hz/dB for F0 and 3.5 Hz/dB for F1. Statistically F2 and F3 did not vary significantly with vocal effort. Formant amplitudes A1, A2, and A3 increased significantly; The amplitudes in the high-frequency range increased more than those in the lower part of the spectrum, revealing a change in spectral tilt. On the average, when the overall amplitude is increased by 10 dB, A1, A2, and A3 are increased by 11, 12.4, and 13 dB, respectively. Using ''auditory'' dimensions, such as the F1 -F0 difference, and a ''spectral center of gravity'' between adjacent formants for representing vowel features did not reveal a better constancy of these parameters with respect to the variations of vocal effort and speaker. Thus a global view is evoked, in which all of the aspects of the signal should be processed simultaneously.
Phonological vowel reduction in
2003
a) Ce Stress To test predictions made by theories of phonological vowel reduction, we require quantitative data to verify and make more precise impressionistic descriptions. Catalan, with phonological vowel reduction in several regional varieties, provides an ideal case study. This paper offers a quantitative description of the stressed and corresponding unstressed vowels of female speakers representing four distinct regional varieties of Catalan – that of Berguedà (representative of Central Catalan – the standard variety), Lleida (Western Catalan), Girona (a northern variety), and Palma (Balearic Catalan). Target vowels appeared in nonsense words which were uttered within a carrier phrase. The formant values for F1-F3 are reported here and compared to impressionistic descriptions. (c) Gi
As a result of the cooperation in the Intas 915 project, annotated speech corpora have become available in three different languages for both read and spontaneous speech of some 4-5 male and 4-5 female speakers per language (6-10 minutes per speaker). These data have been used to study the effects of redundancy on acoustic vowel reduction, in terms of vowel duration, F 1 -F 2 distance to a virtual target of reduction, spectral center of gravity, and vowel intensity. It was shown that in all three (typologically different) languages vowel redundancy increases acoustic reduction in the same way. The reduction of redundant vowels seems to be a language universal.