I think I've found out (well, it was pointed out to me--I can't take credit) why bilingualsearch has so many er...questionable languages listed. It seems that they used iLoveLanguages as the source of their list. The list there says "By Language" but it also has some non-language categories (Universities, Dictionaries) and Pidgin is a category containing sites on various pidgins. Whoever (or whatever) put together the bilingualsearch list also seems to have conflated the Sign Language categories (maybe they thought American and British Sign Languages were the same, because the dominant spoken language in both places is English?). Laziness strikes again!
What's worse, it seems that the York University English Language Institute put together the list of languages for their ESL program the same way. Oy. They should really know better.