John H. McWhorter. 2011. Linguistic simplicity and complexity: Why do languages undress? Berlin: de Gruyter Mouton. 338 pp.

This review article consists of three parts: a presentation of McWhorter’s book, an evaluation of the book, and a proposal for a systematic metric for one version of the notions of simplicity and complexity in languages. McWhorter’s basic thesis, that creoles have simpler grammars than their lexifier languages and simpler grammars than languages transmitted through acquisition in childhood, must begin with rigorous definitions of the terms ‘simplicity’ and ‘complexity’. The paper proposes a way to measure simplicity and complexity. Whether the notions of simplicity or complexity have a heuristic value remains an open question.