Noam Chomsky introduced the concept of communicative competence through his generative grammar theory. Communicative competence refers to a speaker's subconscious ability and ideal capacity for language in terms of grammar, as if they knew a language perfectly without external influences. Performance is the actual production of language in real situations, which can be affected by things like memory limitations or distractions. According to Chomsky, competence is a speaker's internal linguistic knowledge, while performance is the observable use of language. His transformational-generative grammar model uses rules to generate grammatically correct sentences, demonstrating the underlying principles of a language.