Detecting anticipatory effects in speech articulation by means of spectral coefficient analyses.

Few acoustic studies have attempted to examine anticipatory effects in the earliest part of the release of stop consonants. We investigated the ability of spectral coefficients to reveal anticipatory coarticulation in the burst and early aspiration of stops in monosyllables. Twenty American English speakers produced stop (/k,t,p/) - vowel (/æ,i,o/) - stop (/k,t,p/) sequences in two phrase positions. The first four spectral coefficients (mean, standard deviation, skewness, kurtosis) were calculated for one window centered on the burst of the onset consonant and two subsequent, non-overlapping windows. All coefficients showed an influence of vowel-to-consonant anticipatory coarticulation. Which onset consonant showed the strongest vowel effect depended on the specific coefficient under consideration. A context-dependent consonant-to-consonant anticipatory effect was observed for onset /p/. Findings demonstrate that spectral coefficients can reveal subtle anticipatory adjustments as early as the burst of stop consonants. Different results for the four coefficients suggest that comprehensive spectral analyses offer advantages over other approaches. Studies using these techniques may expose previously unobserved articulatory adjustments among phonetic contexts or speaker populations.