The dependence of accommodation processes on conversational experience

Conversational partners accommodate to one another's speech, a process that greatly facilitates perception. This process occurs in both first (L1) and second languages (L2); however, recent research has revealed that adaptation can be language-specific, with listeners sometimes applying it in one language but not in another. Here, we investigate whether a supply of novel talkers impacts whether the adaptation is applied, testing Mandarin-English groups whose use of their two languages involves either an extensive or a restricted set of social situations. Perceptual learning in Mandarin and English is examined across two similarly-constituted groups in the same English-speaking environment: (a) heritage language users with Mandarin as family L1 and English as environmental language, and (b) international students with Mandarin as L1 and English as later-acquired L2. In English, exposure to an ambiguous sound in lexically disambiguating contexts prompted the expected retuning of phonemic boundaries in categorisation for the heritage users, but not for the students. In Mandarin, the opposite appeared: the heritage users showed no adaptation, but the students did adapt. In each case where learning did not appear, participants reported using the language in question with fewer interlocutors. The results support the view that successful retuning ability in any language requires regular conversational interaction with novel talkers.