According to the bioprogram hypothesis it should be possible to rank all languages along a developmental hierarchy in terms of their closeness to or distance from the bioprogram. Bickerton [Bickerton, D. 1984. “The language bioprogram hypothesis and second language acquisition”, in Rutherford, W. E. (a cura di ) Language Universals and Second Language Acquisition, Amsterdam, John Benjamins, pp. 141-161] says that this should give us a measure of the distance between any two languages which are in contact in a learning situation. This should allow us to predict whether the learning of a particular language will be more difficult or easier for one set of learners as opposed to another. Among other things, this means that ‘true’ creoles, ie those which are close to the bioprogram, should be easiest to acquire. If that is so, it is curious that adult pidgin speakers seem unable to acquire Hawaii English Creole. The reasons must be social rather than biological.
- Romaine (1988), a pag.308