Interlocutor identity affects language activation in bilinguals

• We familiarized early and late bilinguals with interlocutors speaking different languages.
• In an audio–visual lexical decision task items were produced by the interlocutors.
• The items were either congruent or incongruent with the interlocutors’ familiarization language.
• During incongruent trials, the response latencies of early bilinguals increased.
• Language activation of early bilinguals are modulated by interlocutor identity.

In bilingual communities, individuals often communicate in one of their languages only, and they adjust to the linguistic background of different interlocutors with ease. What facilitates such efficiency? We investigated whether bilinguals’ language activation is supported by non-linguistic cues (e.g., interlocutor identity). First, in an audio–visual task, early (proficient) and late (less proficient) Basque–Spanish bilinguals were familiarized with six novel interlocutors who spoke either Spanish, Basque, or both languages. Then, participants completed an audio–visual lexical decision task, in which the interlocutors produced test items in Spanish or Basque. Early, but not late, bilinguals’ speed of processing decreased when the language that the interlocutors spoke during familiarization matched the language they spoke at test, relative to test trials when the interlocutors changed languages. Overall, results suggest that proficient and/or early bilinguals benefit from an association between language and interlocutor during (or even before) language comprehension, because they are able to predict the context-appropriate language based on non-linguistic cues, such as interlocutor context.