영어의 운율강화와 어휘경계가 /s/-폐쇄음 자음군 발화에 미치는 영향

Abstract

The present study examined how the effects of prosodic strengthening (arising with prosodic boundary and accent) and lexical boundary (e.g., ‘ice # can’ vs. ‘eye # scan’) are acoustic-phonetically realized on English /s/-stop sequences in a sentence. The results revealed several important points. First, the domain-initial strengthening effect was not strictly confined to the first segment, but it could extend into the second consonant and, at least partially, into the following vowel in the #/sCV/ sequence (e.g., in ‘scan’). However, some effects of domain-initial strengthening were sensitive to the presence or absence of accent, suggesting that domain-initial strengthening is constrained by prominence in English. Second, the accent-induced strengthening effect was robust in all the acoustic measures for the #/sCV/ sequence. Third, prosodic strengthening arising with boundary and accent gave rise to the ‘shortened’ VOT for the voiceless stop in the #/sCV/ sequence, suggesting that prosodic strengthening can operate on the phonetic manifestation of a phonological rule as a way to reinforce the language-specific phonetic feature, which is, in this case, {-spread glottis}. Fourth, domain-initial strengthening and accent-induced strengthening differ substantially in some aspects, suggesting that they may be encoded separately in speech production process. However, two aspects of the prosodic marking are not entirely independent, but they do interact with each other in such a way that accent-induced strengthening is employed not to emphasize every accented word with the same degree, but to put more weight on the accented word that also reflects important positional information. Finally, ‘ice # can’ and ‘eye # scan’ were indeed very differently realized, suggesting that the underlying lexical boundary is signaled by fine-phonetic details even when the sequences occurred phrase-internally where they appeared to be homophonous, at least impressionistically, and syllabified the same. Overall, the results of the present study show that phonetic realization of a /s/-stop sequence is conditioned by an interaction of boundary and prominence factors, which is further modulated by the phonological system of a given language.