Imitation interacts with one's second-language phonology but it does not operate cross-linguistically

This study explored effects of simultaneous use of late bilinguals’ languages on their second-language (L2) pronunciation. We tested (1) if bilinguals effectively inhibit the first language (L1) when simultaneously processing L1 and L2, (2) if bilinguals, like natives, imitate subphonemic variation, (3) if bilinguals’ imitation operates crosslinguistically, and (4) if imitation interacts with phonological structure. Sixteen L1-Czech L2-English speakers heard stimuli with two factors manipulated: language (Czech, English) and Voice Onset Time (VOT) in /p, t, k/ (short, long). They subsequently pronounced English /t/- and /d/-initial words. Speakers’ VOTs in the Czech-Short-VOT, Czech-Extended-VOT, and English-Reduced-VOT conditions were comparable, but VOTs were more English-like after exposure to English-Long-VOT, which applied to both /t/ and /d/.
The conclusions are as follows. (1) Bilinguals’ potentially ineffective L1 inhibition did not affect their L2 production, since exposure to Czech did not lead to VOT reduction. (2) Imitation is not limited to native speech, since bilinguals increased their VOTs following exposure to English-Long-VOT. (3) Imitation did not operate cross-linguistically, since bilinguals’ English productions following Czech-Short-VOT and Czech-Extended-VOT did not differ. Finally, (4) imitation does interact with phonology, since exposure to English long-VOT /t/ resulted in a reduction in prevoicing of its voiced
counterpart, /d/.