Abstract: Language acquisition involves genetic endowment,language experience and universal cognitive functions.Compositional Language Faculty (CLF)holds that language acquisition is possible only when the six or seven fundamental cognition abilities have been developed.CLF,which employs the way of listing,is lack of rigorous criteria for judgment and implementation,resulting in an endless listing of relevant cognition abilities.The six or seven cognitive abilities are lack of systematicity among them and equally lack of verifiability and falsiability.Employing diachronic investigations as the standard to assess a linguistic theory violates the basic requirements of linguistic theory construction.

Key words: Compositional Language Faculty, language acquisition, theory construction