Patterns of Assimilation Nasality in English as a Function of Vowel Height

Assimilation nasality patterns for high, mid and low vowels were studied in two dialects of North American English (Canadian & southeastern American). Native speakers (n=24) produced CVC, NVC, CVN and NVN tokens. The vowel portion of each oral and nasal acoustical signal was transduced by a Nasometer, digitized, and the degree of nasalance established as: % nasalance = nasal rms/(nasal + oral rms) x 100. The high vowels in both dialects exhibited significantly more assimilation nasality than lower vowels in all nasal contexts. In addition, anticipatory nasalization was significantly more extensive than carry-over nasalization for all speakers and all vowels, and significantly more so for the southeastern American speakers than those who spoke Canadian English.