Phonetic Interpretation Papers in Laboratory Phonology VI: Effects on word recognition of syllable-onset cues to syllable-coda voicing

TLDR: Nguyen et al. as mentioned in this paper showed that the durational difference in stressed syllables can be 100 ms or more, and it is well-established as one of the strongest perceptual cues to whether the coda is voiced or voiceless.

Abstract: It is well known that syllables in many languages have longer vowels when their codas are voiced rather than voiceless (for English, cf. Jones, 1972; House & Fairbanks, 1953; Peterson & Lehiste, 1960; for other languages, including exceptions, see Keating, 1985). In English, the durational difference in stressed syllables can be 100 ms or more, and it is well-established as one of the strongest perceptual cues to whether the coda is voiced or voiceless (e.g. Denes, 1955; Chen, 1970; Raphael, 1972). More recently, van Santen, Coleman & Randolph (1992) showed for one General American speaker that this coda-dependent durational difference is not restricted to syllabic nuclei, but includes sonorant consonants, while Slater and Coleman (1996) showed that, for a British English speaker, the differences tended to be greatest in a confined region of the syllable, the specific location being determined by the syllable’s segmental structure. In a companion study to the present paper (Nguyen & Hawkins, 1998; Hawkins & Nguyen, submitted), we confirmed the existence of the durational difference and showed that it is accompanied by systematic spectral differences in four accents of British English (one speaker per accent). For three speakers/accents, F2 frequency and the spectral centre of gravity (COG) in the /l/ were lower before voiced compared with voiceless codas, as illustrated in Figure X.1. (The fourth speaker, not discussed further here, had a different pattern, consistent with the fact that his accent realises the /l/-/r/ contrast differently.) Since F1 frequency in onset /l/s did not differ due to coda voicing, whereas both F2 frequency and the COG did, we tentatively concluded that our measured spectral differences reflect degree of velarisation, consistent with impressionistic observations. Thus the general pattern is that onset /l/ is relatively long and dark when the coda of the same syllable is voiced, and relatively short and light when the coda is voiceless. Do these differences in the acoustic shape of onset /l/ affect whether the syllable coda is heard as voiced or voiceless? If they do, the contribution of the onset is likely to be small and subtle, because the measured acoustic differences are small (mean 4.3 ms, 11 Hz COG, 16 Hz F2 over three speakers). However, though small, the durational differences are completely consistent and strongly statistically significant. Spectral differences are more variable but also statistically significant. Moreover, at least some can be heard. Even if only the more extreme variants provide listeners with early perceptual information about coda voicing, there are far-reaching implications for how we model syllableand word-recognition, because the acoustic-phonetic properties we are concerned with are in nonadjacent segments and, for the most part, seem to be articulatorily and acoustically independent of one another. So, by testing whether these acoustic properties of onset /l/ affect the identification of coda voicing, we are coming closer to testing the standard assumption that lexical items are represented as sequences of discrete phonemic or allophonic units, for in standard phonological theory, longer duration and