Uniformity and diversity

This essay discusses language uniformity and diversity in the light of recent developments of the minimalist program (Hauser et al. 2002; Chomsky 2008; Berwick & Chomsky 2011, and much related work). It pursues two leading ideas. First, Universal Grammar (UG) is maximally minimal: hence early internal language (I-language) is largely uniform across individuals, language variation being mainly or entirely confined to externalization. Second, the mapping from I-language to external language (E-language) is non-isomorphic (the Non-isomorphy Generalization), morphological processes such as agreement and case marking being E-language phenomena, taking place in the externalization component. The first line of reasoning converges with many of Chomsky’s recent ideas, the second one is more divergent. Keywords: E-language; externalization; I-language; person; tense; non-isomorphy generalization