Large-scale Acoustic Analysis of Dialectal and Social Factors in English /s/-retraction

Abstract

The retraction of /s/ in /str/, eg street, is a sound change found in certain English dialects. Previous work suggests that /s/-retraction arises from lower spectral frequency /s/ in /str/. The extent to which /s/-retraction differs across English dialects is unclear. This paper presents results from a large-scale, acoustic phonetic study of sibilants in 420 speakers, from 6 spontaneous speech corpora (9 dialects) of North American and Scottish English. Spectral Centre of Gravity was modelled from automatic measures of word-initial sibilants. Female speakers show higher frequency sibilants than males, but more so for /s/ than /S/; /s/ is also higher in American than Canadian/Scottish dialects; /S/ is surprisingly variable. /s/-retraction, modelled as retraction ratios, is generally greater for /str/ than /spr skr/, but varies by dialect; females show more retraction in /str/ than males. Dialectal and social factors clearly influence /s/-retraction in English clusters /sp st sk/, /spr skr/, and /str/