Effects of prosodic strengthening and lexical boundary on /s/-stop sequences in English Free

This study examined how the effects of prosodic strengthening (from 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. First, the domain-initial strengthening effect was not strictly confined to the first segment, but could extend into the second consonant and, at least partially, into the following vowel in the #/sCV/ sequence (e.g., in “scan”). Second, the accent-induced strengthening effect was robust in all 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 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. 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.