This document discusses the concepts of performance and competence in linguistics. It defines performance as the actual language produced by speakers, as seen in corpora, while competence refers to a speaker's internalized knowledge of language. The document notes that performance is influenced by factors like memory limitations, attention, social context, and individual style. A performance grammar aims to describe language as it is spontaneously used, including features like hesitations, while a competence grammar describes the systematic rules of a language.