A cross-linguistic investigation of locus equations as a phonetic descriptor for place of articulation

Sussman, Harvey M.; Hoemeke, Kathryn A.; Ahmed, Farhan S.

doi:10.1121/1.408178

Cited by 80 publications

(68 citation statements)

References 16 publications

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“…Regression line fits to these plots reveal a linear relationship between F2yowel and F2 ons ' The regression lines for different consonants, or the locus equations that represent them, may be characterized by their slopes and intercepts. It has been found that the locus equation lines for different stop consonants occupy distinct regions in slope-by-intercept space (at least, if they are based on productions of speakers of a single language; Sussman, Hoemeke, & Ahmed, 1993). Locus equations represent an invariant that is not found in a particular token utterance, but rather over sets of consonant-vowel (CV) syllables that share their initial consonant.…”

Section: Locus Equationsmentioning

confidence: 99%

On the relevance of locus equations for production and perception of stop consonants

Brancazio

Fowler

1998

Perception & Psychophysics

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Weexamined the possible relevance of locus equations to human production and perception of stop consonants. The orderly output constraint (OOC) of Sussman, Fruchter, and Cable (1995) claims that humans have evolved to produce speech such that F2 at consonant release and F2 at vowel midpoint are linearly related for consonants so that developing perceptual systems can form representations in an F2 0 ns -by-F2vowel space. The theory claims that this relationship described by locus equations can distinguish consonants, and that the linearity oflocus equations is captured in neural representations and is thus perceptually relevant. Weinvestigated these claims by testing how closely locus equations reflect the production and perception of stop consonants. In Experiment 1, we induced speakers to change their locus equation slope and intercept parameters systematically, but found that consonants remained distinctive in slope-by-intercept space. In Experiment 2, we presented stop-consonant syllables with their bursts removed to listeners, and compared their classification error matrices with the predictions of a model using locus equation prototypes and with those of an exemplar-based model that uses F2 0 ns and F2vowelJ but not locus equations. Both models failed to account for a large proportion of the variance in listeners' responses; the locus equation model was no better in its predictions than the exemplar model. These findings are discussed in the context of the OOC.It is well known among speech scientists that formant transitions provide listeners with important information for identifying the stop consonants Ib/, Id/, and 191 in syllable-initial position. However, it is a matter of debate how such transition information is used. In particular, the importance of these highly context-sensitive transitions to perceivers provides a challenge for theorists who claim that listeners use invariant information to identify stops (e.g., Fowler, 1986;Stevens & Blumstein, 1981). One early hypothesized invariant was a locus to which all second-formant transitions of a given consonant pointed back in time by extrapolation (Delattre, Liberman, & Cooper, 1955). Locus points were found for Ibl and Id/, but 191 required two loci; and even the loci for Ibl and Idl proved controversial. For example, Ohman (1966) found that the locus points were not invariant, and that they changed, depending on the identity ofa preceding vowel. Later, Kewley-Port (1982) made extensive acoustic measurements of formant transitions for the stop consonants in various vocalic contexts and concluded against any invariant in the transition. Transitions, therefore, appear to be inherently context sensitive. As a result, theories assuming both the importance of invariance for perception and a role for formant transitions have taken different directions. One is to assume, as motor theorists have, that This research was supported by NICHD Grant HD-OI994 to Haskins Laboratories. We would like to thank Harvey Sussman, Bjorn Lindblom, Doug Whalen, and an anonym...

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Section: Locus Equationsmentioning

confidence: 99%

On the relevance of locus equations for production and perception of stop consonants

Brancazio

Fowler

1998

Perception & Psychophysics

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“…For technical reasons, F3 was unreliable in the Yanyuwa and Yindjibarndi data, and will therefore not be reported here for the six speakers involved. (14) Locus equations: Locus equations (Lindblom 1963, Sussman, Hoemeke & Ahmed 1993 are an attempt to quantify the F2 transition between the consonant and the vowel across a variety of vowel contexts. Locus equations aim to capture the 'average' amount of coarticulation between a given consonant and multiple vowel contexts.…”

Section: Duration and Formant Analysesmentioning

confidence: 99%

VC vs. CV syllables: a comparison of Aboriginal languages with English

Tabain¹,

Breen

Butcher³

2004

Journal of the International Phonetic Association

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Traditionally, phonological theory has held that the CV syllable is the basic syllable type across the world's languages. Recently however, Breen & Pensalfini (1999) have challenged the primacy of the CV syllable in phonological theory with data from Arrernte, an Aboriginal language spoken in central Australia. In this study, we set out to see if there is any acoustic phonetic basis to Breen & Pensalfini's claim. We examine real-word data from one speaker of Arrernte, five speakers of English, and three speakers each of Yanyuwa and Yindjibarndi (these are two other Aboriginal languages). Using F2 and F3 measures of the consonant, and locus equation measures, we find that CV does show more stability than VC in the English speakers' data, but that for the Aboriginal language speakers' data, there is a parity between the CV and VC measures. We suggest that this greater parity may be a necessary constraint on languages which have multiple places of articulation (six in the case of the Aboriginal languages studied here). We propose an alternative view of suprasegmental organization, and we suggest that more work is needed in order to understand the phonetic bases of suprasegmental structure.

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“…This orderly plot captures a higher order and emergentlike acoustic commonality-namely, a vowel normalization of the F2 transition within each stop place category. Higher order locus equation coefficients-slope and yintercept-when serving as predictor variables in a discriminant analysis, were shown to correctly classify labial, alveolar, and velar stop place of articulation with 100% accuracy (Sussman et al, 1991 the slope of the regression function is proportional to the extent ofCV coarticulation being used by the speaker (see Figure 10 in Sussman et al, 1993). The consistently linear scatterplots, as documented across languages, gender, and speaking conditions, have recently been interpreted as possibly serving a functional role in speech perception and the representational encoding (viz., mapping) of acoustic-based place of articulation categories (Sussman, Fruchter, & Cable, 1995).…”

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confidence: 99%

Locus equations as phonetic descriptors of consonantal place of articulation

Sussman

Shore

1996

Perception & Psychophysics

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This experiment tested whether locus equation coefficients, slope, and y-intercept could serve as indices of place ofarticulation for obstruents sharing the same place ofarticulation across different manner classes. Locus equations for 22 speakers were derived from eVltl words with initial voiced stop Idl, voiceless aspirated stop It/, nasal Inl, voiced fricative Izl, and voiceless fricative lsi preceding 10 vowel contexts. Post hoc tests revealed Idl = Izl = Inl for slope means. Voiced Idl and voiceless It I were also equivalent when F2 transition onset measurement points were equated. Scatterplots of locus equation coefficients revealed three nonoverlapping and distinct clusters when the diverse coronal group was compared with labials and velars. A discriminant analysis using slope and y-intercept as predictors successfully categorized all five coronals into one alveolar group with 87.1% accuracy. The collective results support the contention that locus equations can serve as effective phonetic descriptors of consonant place of articulation across manner classes.Locus equations are linear regressions of the onset of F2 transitions on their offsets measured in the vowel nucleus (Lindblom, 1963). Frequency coordinates coding F2 transitions ofallophonic variants ofa given stop place category (e.g., beat, bet, bat, boot, but, boat, bought, bait, etc.) This orderly plot captures a higher order and emergentlike acoustic commonality-namely, a vowel normalization of the F2 transition within each stop place category. Higher order locus equation coefficients-slope and yintercept-when serving as predictor variables in a discriminant analysis, were shown to correctly classify labial, alveolar, and velar stop place of articulation with 100% accuracy (Sussman et al., 1991 the slope of the regression function is proportional to the extent ofCV coarticulation being used by the speaker (see Figure 10 in Sussman et al., 1993). The consistently linear scatterplots, as documented across languages, gender, and speaking conditions, have recently been interpreted as possibly serving a functional role in speech perception and the representational encoding (viz., mapping) of acoustic-based place of articulation categories (Sussman, Fruchter, & Cable, 1995).The acoustic correlates of consonantal place of articulation, however, are many and varied. Burst information, onset spectra, and formant transition motion have all been implicated, to greater or lesser extents, as perceptual cues for place ofarticulation (see, e.g., Blumstein & Stevens, 1979, 1980Dorman, Studdert-Kennedy, & Raphael, 1977;Eek & Meister, 1995;Furui, 1986; KewleyPort, 1983;Lahiri, Gewirth, & Blumstein, 1984; Nossair & Zahorian, 1991;Ohde, Haley, Vorperian, & McMahon, 1995;Walley & Carrell, 1983). Locus-equation-based analyses can offer additional insights into the role of the F2 transition onset-offset combination as a contributing cue for consonant place of articulation. Though the taxonomic value of locus equations to date has primarily been as a phonetic descri...

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A cross-linguistic investigation of locus equations as a phonetic descriptor for place of articulation

Cited by 80 publications

References 16 publications

On the relevance of locus equations for production and perception of stop consonants

On the relevance of locus equations for production and perception of stop consonants

VC vs. CV syllables: a comparison of Aboriginal languages with English

Locus equations as phonetic descriptors of consonantal place of articulation

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