ABSTRACT
Following Chomsky, modern studies of linguistics and language development make a distinction between performance and competence. Performance refers to the actual acts of language production or comprehension. Competence, in this sense, does not carry its common usage of 'ability to do' but rather refers to the knowledge and rules which are necessary to particular acts or performances. Linguistic competence refers to the system of rules representing a speaker/hearer's abstract knowledge of his language. A description of competence is not a psychological theory of performance in real situations. It does not represent psychological contents or operations involved in producing or interpreting sentences. It represents the grammatical knowledge that is a necessary prerequisite to performing these operations. Various factors may impede the application of this underlying competence. Since psychological data are restricted to describing acts or performances any studies of competence are indirect and must contend with these distorting factors. Since competence cannot be studied directly one is bound to ask whether it is a useful construct in accounting for performance.
