What bilinguals tell us about culture, cognition, and language.

In the last 25 years, cognitive scientists have come to see that usingmore than one language is a natural circumstance of human experience, not an exceptional condition that produces disordered speaking or thinking (1). The revision of previously held negative views about bilingualism is largely attributable to the finding that although bilinguals appear to activate both languages when reading, listening to speech, and speaking one language alone, they do not suffer notable disruptions (2). Bilingual speakers can choose the language they wish to speak, but at the same, switch back and forth from one language to the other, often in midsentence, with others who are similarly bilingual. The evidence suggests that the consequences of bilingualism are largely positive, with features of bilingual minds and brains reflecting the benefits of a life spent negotiating the presence of two languages and acquiring the skill to select the appropriate language in the intended context (3, 4). In a fascinating PNAS report, Zhang et al. (5) demonstrate that bilingual speakers are sensitive to cultural cues in the environment that signal the presence of the native language. Contrary to the claim that bilingualism confers benefits to those who speak more than one language, the form of the sensitivity demonstrated in the Zhang et al. research is negative, with slower speech when speaking the second language, L2, in the presence of first language, L1. Most dramatically, these disruptions to L2 speech occur when bilinguals are speaking to the faces of other bilinguals with the same L1. Zhang et al. (5) show that when Chinese– English bilinguals speak to Chinese faces, they speak English, their L2, more hesitantly than when they speak to Caucasian faces. Critically, the experiments that generated these data were conducted in the United States with bilinguals immersed in American culture and in English as the dominant language of the environment. The fact that their English changes when speaking to a Chinese vs. Caucasian face suggests that native language cues and culture are powerful determinants of language performance. Why faces? For infants during early stages of language development, the face is the primary source of information about the connection between language and the social environment (6). For infants exposed to two languages from birth, faces may be a special cue to which language is being spoken. A remarkable study by Sebastián-Gallés et al. (7) showed that crib bilinguals can discriminate which of two languages is being spoken on the basis of a silent video of speaking faces,