Grant Berry, a 2016 PIRE fellow, has recently presented a poster at the 2016 LabPhon conference.
We investigate the plasticity of phonological boundaries in discourse in a lingua franca by tracking the production of 34 Spaniards conversing with two Dutch confederates in English across two speech styles, and we focus on incremental changes in two key English vowel contrasts. The first, /i/-/ɪ/, is not made by Spanish speakers in aggregate but reliably produced by the Dutch confederates. The second, /ɛ/-/æ/, is produced by Spaniards, but not by Dutch confederates. We assessed degree of merger in each of ten normalized time bins with the Pillai score. Results indicate that Spaniards align with the Dutch confederates in their production of these contrasts, merging /ɛ/ and /æ/ and gradually separating /i/ and /ɪ/, rather than adopting standard English production. We found greater merger overall in informal speech, but an interaction with time for the /i/-/ɪ/ contrast indicates that /i/ and /ɪ/ gradually separate in informal speech. Conversely, there is no effect of time for the /ɛ/-/æ/ contrast: Spaniards merge /ɛ/ and /æ/ when conversing with the Dutch confederates significantly more in informal speech, but the magnitude is static throughout each interview. Finally, proficiency modulates alignment: the most proficient speakers separate /i/-/ɪ/ and merge /ɛ/-/æ/ more than less proficient speakers.