Help or hindrance: How violation of different assimilation rules affects spoken-language processing

Abstract

Recent phoneme detection studies showed that spoken-language processing is inhibited by violation of obligatory assimilation [e.g., Otake et al. (1996)]. A phoneme detection experiment was designed to replicate this effect with German fricative assimilation. German fricative assimilation is progressive and applies within syllables. The velar fricative [x] occurs after back vowels, the palatal fricative [ç] after front vowels. In contrast to previous findings, listeners detected [x] faster when violation occurred. A second experiment explored whether these results are due to the tested assimilation applying within syllables, whereas earlier experiments tested assimilation across syllables. Again, listeners detected [x] faster when the assimilation rule was violated across a syllable boundary. The discrepancy with the earlier results might be due to the German fricative assimilation rule being progressive, while earlier experiments tested regressive assimilation. A third experiment tested German place assimilation for nasals. Regressive place assimilation in German is obligatory within syllables. A velar stop /k/ specifies the place for the preceding nasal /ŋ/. This time listeners detected the target phoneme /k/ more slowly when the assimilation was violated. The results show that whereas violation of regressive assimilation inhibits processing, violation of progressive assimilation speeds up processing.