Lexical status effects on compensation for fricative assimilation

Abstract

In German, word-initial voiced fricatives may be devoiced if they follow /t/. This assimilation could make recognition of words beginning with /v/ harder, since there may be competing words beginning with /f/, but will not affect words beginning with /z/, since initial /s/ in German is illegal. Previous research has shown that speakers indeed produce more assimilation across word boundaries than across phrase boundaries for /z/, but inhibit the assimiliation across word boundaries for /v/. In the present study, German listeners identified the fricative continua /f–v/ and /s–z/, across word-versus-phrase boundaries, in viable-versus-nonviable contexts for assimilation. Less voicing was required for a /v,z/ judgment in viable than in nonviable assimilation contexts. This context effect was larger after a word boundary than after a phrase boundary. Within the viable-context condition, a prosodic effect appeared for /f–v/, with less voicing required for /v/ judgments after a word than a phrase boundary, but no such effect appeared for /s–z/. This asymmetry reverses the difference observed in production. Thus, listeners adjust phoneme category boundaries to compensate for prosodically conditioned variation where such adjustment is functional for word recognition, but show less compensation where adjustment would have no functional consequences.