The body of theory on speech production and speech disorder developed prior to Descartes has been so neglected by historians that its very existence is practically unknown today. Yet it provides a framework for understanding the speech process which is not only comprehensive and coherent, but of great relevance to current debates on issues of language performance and applied linguistics. Current theoretical difficulties stem largely from initial errors of Descartes; whereas earlier theoretical formulations, while outlining a bio-mechanics of speech, retain the central role of the human agent.