Perro or txakur? Bilingual language choice during production is influenced by personal preferences and external primes

Bilinguals living in a bilingual society continuously need to choose one of their languages to communicate a message. Sometimes, the circumstances (e.g., the presence of a monolingual) dictate language choice. When surrounded by other bilinguals, however, the bilinguals themselves can often decide which language to use. While much previous research has assessed language production when language selection is predetermined, we assessed how bilinguals choose the naming language themselves. We focused on the role of personal language preferences and examined to what extent personal preferences might be affected by external, suggestive language primes. Spanish-Basque bilinguals were asked to name pictures in their language of choice. Pictures were either presented on their own or were preceded by a linguistic or non-linguistic prime. In a separate session, participants were asked which language they preferred for each picture. Language choice during voluntary picture naming was related to personal language preferences. A bilingual was more likely to name a picture in the language they preferred for that specific picture. Furthermore, bilinguals were more likely to choose the language matching the preceding linguistic or non-linguistic prime. Effects of primes and preferences were additive and the influence of language preference on choice was equally strong in the primed and no-prime tasks. In addition to modulating language choice, following preferences and primes was also associated with faster responses. Together, these findings show that initial stages of language production and language choice are not just modulated by external primes but also by a bilingual's individual preferences.