Linguistic change as a result of speech defects

Someone sent me the item about the drunken Galician whoremonger who got trapped in a lavoir (Spanish narrative), and I put it on in the background. Galician normally sounds like dodgy rural Spanish with a bit of Portuguese thrown in, but the first interviewee threw me completely. A completely new dialect? Nope: check his front teeth. Now I want to hear recordings of his children. (Re the Castilian lisp: there's now a decent WP article called Phonological history of Spanish coronal fricatives.)