Adult Japanese speakers judged the grammaticality of isolated simple bitransitive sentences involving an illegitimate extra argument in addition to three legitimate arguments. The sentences therefore violated Chomsky's principle of Full Interpretation. The extra argument was a mere repetition of a preceding legitimate argument. The role of emphasis placed on the extra argument in the judgments was studied. The role of argument type, subjective and objective, was also investigated for sentences different in argument order, basic and transformed. Findings showed first that the sentences were judged moderately on a 7-point scale. Second, the transformed sentences were judged less grammatical than basic sentences. Third, sentences having two objective arguments (objective sentences) were judged more grammatical than those having two subjective arguments (subjective sentences) both for the basic and for the transformed sentences. Lastly, for the transformed sentences emphasis slightly increased the judged grammaticality of both the subjective and the objective sentences. These endings are not compatible with Chomsky's theory of knowledge of language that he claims every speaker possesses.

Key words: Principle of Full Interpretation, grammaticality judgments, bitransitive sentences, emphasis, argument order