The relative degree of difficulty of L2 Spanish /d, t/, trill, and tap by L1 English speakers: Auditory and acoustic methods of defining pronunciation accuracy.

摘要

This study has investigated the L2 acquisition of Spanish word-medial /d, t, r, (fish hook)/, word-initial /r/, and onset cluster /(fish hook)/. Two similar experiments were designed to address the relative degree of difficulty of the word-medial contrasts, as well as the effect of word-position on /r/ and /(fish hook)/ accuracy scores. In addition, the effect of vowel height on the production of [r] and the L2 emergence of the svarabhakti vowel in onset cluster /(fish hook)/ were investigated. Participants included 34 Ll English speakers from a range of L2 Spanish levels who were recorded in multiple sessions across a 6-month or 2-month period. The criteria for assessing segment accuracy was based on auditory and acoustic features found in productions by native Spanish speakers. In order to be scored as accurate, the L2 productions had to evidence both the auditory and acoustic features found in native speaker productions. L2 participant scores for each target were normalized in order to account for the variation of features found across native speaker productions. The results showed that word-medial accuracy scores followed two significant rankings (from lowest to highest): /r = d = (fish hook) = t/ and /r = (fish hook) = d = t/; however, when scores for /t/ included a voice onset time criterion, only the ranking /r = (fish hook) = d = t/ was significant. These results suggest that /r/ is most difficult for learners while /t/ is least difficult, although individual variation was found. Regarding /r/, there was a strong effect of word position and vowel height on accuracy scores. For productions of /(fish hook)/, there was a strong effect of syllable position on accuracy scores. Acoustic analyses of taps in onset cluster revealed that only the experienced L2 Spanish participants demonstrated svarabhakti vowel emergence with native-like performance, suggesting that its emergence occurs relatively late in L2 acquisition.