A common selection mechanism at each linguistic level in bilingual and monolingual language production.

The primary goal of research on the functional and neural architecture of bilingualism is to elucidate how bilingual individuals' language architecture is organized such that they can both speak in a single language without accidental insertions of the other, but also flexibly switch between their two languages if the context allows/demands them to. Here we review the principles under which any proposed architecture could operate, and present a framework where the selection mechanism for individual elements strictly operates on the basis of the highest level of activation and does not require suppressing representations in the non-target language. We specify the conjunction of parameters and factors that jointly determine these levels of activation and develop a theory of bilingual language organization that extends beyond the lexical level to other levels of representation (i.e., semantics, morphology, syntax and phonology). The proposed architecture assumes a common selection principle at each linguistic level to account for attested features of bilingual speech in, but crucially also out, of experimental settings.