Grammar is now widely regarded as a substantially biological phenomenon, yet the problem of language evolution remains a matter of controversy among Linguists, Cognitive Scientists, and Evolutionary Theorists alike. In this paper, I present a new theoretical argument for one particular hypothesis—that a “Language Acquisition Device” of the sort first posited by Noam Chomsky might have evolved via the so-called “Baldwin Effect”. Close attention to the workings of that mechanism, I argue, helps to explain a previously mysterious feature of the Language Acquisition Device—the sheer variety of languages it allows the child to learn—thereby revealing a far stronger case than adherents of the hypothesis have previously supposed. A further unheralded consequence of the hypothesis is a conceptual shift in the Chomskyan understanding of language, wherein the essentially public nature of language is freshly emphasised. This has the effect of bringing the Chomskyan view into closer accord with Saussurean accounts of language, as well as with recent trends in evolutionary theory.