Electrophysiological evidence for endogenous control of attention in switching between languages in overt picture naming.

Language switching in bilingual speakers requires attentional control to select the appropriate language, for example, in picture naming. Previous language-switch studies used the color of pictures to indicate the required language thereby confounding endogenous and exogenous control. To investigate endogenous language control, our language cues preceded picture stimuli by 750 msec. Cue-locked event-related potentials (ERPs) were measured while Dutch-English bilingual speakers overtly named pictures. The response language on consecutive trials could be the same (repeat trials) or different (switch trials). Naming latencies were longer on switch than on repeat trials, independent of the response language. Cue-locked ERPs showed an early posterior negativity for switch compared to repeat trials for L2 but not for L1, and a late anterior negativity for switch compared to repeat trials for both languages. The early switch-repeat effect might reflect disengaging from the nontarget native language, whereas the late switch-repeat effect reflects engaging in the target language. Implications for models of bilingual word production are discussed.