  There are two problems with this ‘language bioprogram  hypothesis,’ as it is known in the creolization literature. The first concerns the claim (e.g., Bickerton 1981:43-70) that even  creoles that developed in quite different areas of the world, and in  complete isolation from one another, bear “uncanny  resemblances” (Pinker 1994:25) to each other, not just in  respecting the constraints of UG, but — even more surprisingly  — in using fundamentally the same means to elaborate their root pidgins (e.g., in using the same syntactic devices to mark tense,  aspect and modality). The stronger claim made by Bickerton —  that Creoles use the same devices for the same grammatical purposes  — is simply not true. For example, as Myhill (1991) argues,  Jamaican Creole, Louisiana Creole, Mauritian Creole and Guyanese  Creole mark tense, aspect and modality in ways that are quite  different from those that Bickerton (1981) proposed as universal.  (See, however, Mufwene 1999 for a case that confirms Bickerton's  predictions.) The weaker claim — that creoles respect the  constraints imposed by UG — has not, so far as I know, been  contested. So we will assume, in what follows, that creoles, like  other NLs, respect UG. The important question for our purposes is:  how does this come about?