Pre-nasal short-a in Northern California: Merged in formant space with /ɛ/, but distinct in duration and degree of nasal coarticulation

Abstract

Short-a, or /æ/, production varies substantially across American English dialects and is noted to be useful in describing regional pronunciation differences. The current study examines the production and perception of /æ/ in California English, which raises in words with a final nasal coda (both velar and non-velar nasals). We explore both the acoustic characteristics of this potential merger with /ɛ/, along with lexical confusability between words with /æ/ and /ɛ/ in prenasal position. Productions of 32 native California speakers reveal that the formant space of prenasal /æ/ indeed overlaps with /ɛ/. However, these vowels have reliably different patterns of two secondary acoustic features: duration and nasal coarticulation. /æ/ is produced with both a longer duration and a greater degree of nasal coarticulation than /ɛ/. Results from a lexical identification task presenting unaltered, as well as duration-neutralized, items to 50 listeners reveal that these vowels are not confusable despite considerable formant overlap. Furthermore, modeling results indicate that greater differences in nasalization between prenasal /æ/-/ɛ/ pairs lead to more accurate identification. Overall, the results from this study indicate that these secondary features help maintain the perceptual distinctiveness of /æ/-/ɛ/ words where formant merger has taken place.