Population Movements and Contacts in Language Evolution

Publications such as Thomason & Kaufman (1988) and Thomason (2001, 2002) have perpetuated, without fundamental support, the distinction between internallyand externally-motivated language changes. They suggest that the two kinds of changes are different in nature and that those induced by language contact have not contributed to language speciation in the same way as those owing (principally) to language-internal mechanisms. Putatively, genetic classifications should be based only on correspondences suggested by internally-motivated change. Thus, they conclude that creoles cannot be classed genetically, because, in their case, contact was so extensive that the comparative method cannot be applied to them in informative ways. This disjoint view of language diversification, which has treated creoles as children out of wedlock (Mufwene 1997b, 2001), is so deeply entrenched in linguistics that it is repeated both in general introductions to linguistics and in historical linguistics textbooks. When the latter kinds of books cover the development of creoles at all as part of their subject matters, they also claim that these vernaculars are genetically “exceptional,” if not unnatural, because they have not emerged in the “usual” and/or “natural” way. See, e.g. Hock & Joseph (1996, critiqued in Mufwene 1998, 2001). Heine & Kuteva (2005) are rather exceptional in arguing that Europe is a linguistic area, one in which language contact accounts for the wide diffusion of several grammatical features, suggesting that the correspondences that obtain among several Indo-European languages are not necessarily due to common inheritance. It can be concluded from the book that one must know a substantial amount of the histories of particular populations before determining whether their shared linguistic materials are due to diffusion through contact or to shared ancestry. Thus, the comparative method can in principle not be used unilaterally, without taking into account the histories of the relevant populations, in order to determine whether or not two language varieties are genetically related (see,