hours of classroom instruction in a second language, and semantically related words from unrelated ones with as little as 63 hours. These reliable N400 effects were accompanied by chance level overt word and relatedness judgments, highlighting the sensitivity of ERP measures to early, implicit aspects of learning. More typical bilinguals show N400 priming and semantic congruity effects in both their languages, with the timing (and to a lesser extent the amplitude) of these effects a function of language proficiency and age of acquisition – being later and smaller for less well-learned languages.
