External Sandhi in a Second Language: The Phonetics and Phonology of Obstruent Nasalization in Korean-Accented English

Abstract

This article presents the results of an acoustic study of nasal assimilation and gestural overlap at word boundaries in Korean and Korean-accented English. Twelve speakers of Seoul Korean recorded phrases containing obstruent#nasal and obstruent#obstruent sequences in both Korean and English. Nasalization of the word-final obstruent, predicted by the rules of Korean phonology, occurred in 93% of obstruent#nasal sequences in Korean and in 32% of such sequences in Korean-accented English, a rate of application higher than that reported in most other studies of external sandhi alternations in nonnative speech. Acoustic analysis found categorical nasalization in the L1 Korean productions, but both categorical and gradient nasalization, along with a high degree of inter- and intraspeaker variation, in the L2 English productions. For a subset of speakers, there was a significant correlation between quantitative measures of nasalization in English and measures of consonant overlap in the English obstruent#obstruent sequences. An analysis in terms of articulatory gestures and the coupled-oscillator model of speech planning is supported. The analysis is based on the articulatory phonology model (Browman & Goldstein 1990a,b, 1992, 2000, Goldstein et al. 2006), though with modifications. Implications for phonetic and phonological representations, and for speech planning in both L1 and L2, are explored.