Detecting palatalization in spontaneous spoken English

Abstract

An analysis is presented of palatalization from /s/ to [ʃ] at word boundaries in UK English. Previous work has considered the effect of lexical frequency (LF) on this phenomenon, but without combining acoustics and spontaneous speech in one study, which is undertaken using data gathered from the Audio BNC (http://www.phon.ox.ac.uk/AudioBNC). 5,197 word pairs are analyzed across five phonological contexts, comparing the acoustics of test tokens subject to palatalization (e.g. /s/ in miss you), to control tokens containing non-alternating [s] (miss it) or [ʃ] (mission, wish it, wish you). Word and segment boundaries were obtained via forced alignment, but hand-checked. The spectral moments and duration of each fricative were measured; following vowel duration and formant values were also extracted. LF was calculated using the Audio BNC. Results show that the spectral center of gravity (CoG) of /s/ before /j/ (miss you) is intermediate (p<0.01) between those of [s] and [ʃ]. Furthermore, CoG of test tokens correlates negatively with LF, indicating increased palatalization in high-frequency contexts. A supervised clustering analysis shows that /s/ before /j/ is distinct from both [s, ʃ]. This supports the view of palatalization as gestural overlap, which increases with LF in casual or fast speech.