Acoustic analysis of a sound change in progress: The consonant cluster /stɹ/ in English

For some speakers of English, realization of the fricative in the consonant cluster /stɹ/may be undergoing a sound change in progress. Previous reports suggest that /s/ is being realized as the postalveolar fricative [ʃ], with the approximant /ɹ/ as a possible trigger. Research in sociolinguistics also indicates that there may be various intermediate stages of the change, falling somewhere between a typical /ʃ/ and /s/. However, information about the precise phonetic characteristics of these novel variants is still sparse, and existing sociolinguistic studies have not compared speakers’ realization of /stɹ/ to their typical /s/ and /ʃ/ productions. This paper uses the acoustic measurement of spectral peak to compare ten English speakers’ productions of the onsets /ʃ/, /ʃɹ/, /stɹ/, and /s/. The findings suggest that the majority of tokens produced by these speakers fall within their normal range for /ʃ/, with only limited evidence of intermediate forms. It is proposed that spectral peak measurement seems to be a stable method for use in future research categorizing variants of /stɹ/. However, this should include comparison to subjects’ normal /ʃ/ productions.