Nonfluent aphasia and the evolution of proto-language

This paper briefly explores the relevance of patterns of related symptoms of nonfluent aphasia arising from left inferior frontal brain damage for the evolution of speech, language and gesture. I discuss aphasic lexical speech automatisms (LSAs) and their resolution with recovery into agrammatism with apraxia of speech and draw parallels between this recovery and the early evolution of language to protospeech and protosyntax. I focus attention on the most common forms of LSAs, expletives and the pronoun + modal/aux subtype, and propose that further research into these phenomena can contribute to the debate on the evolution of speech and language. (C) 2009 Published by Elsevier Ltd.