An acoustic analysis of labialization of coronal nasal consonants in American English

Abstract

A challenge for speech recognition models is to account for the variation between natural connected speech forms and the canonical forms of the lexicon. This study focuses on one particular sound change common in conversational speech, in which word-final coronal nasal consonants undergo place assimilation toward following word-initial labial consonants. Formant frequency measurements were taken from words ending with coronal nasal consonants in potentially assimilating sentence contexts, and identical words ending in labial nasal consonants, across vowel contexts. The frequency of the second formant at vowel offset and during nasal closure was found to be sufficient to discriminate between underlying forms. There was evidence that even strongly-assimilated coronal segments differ on the basis of these cues from their pure labial counterparts. It is hypothesized that listeners can use these acoustic cues to uncover the intended place of articulation of assimilated segments, without recourse to phonological inference or sentence context.