This document discusses language variations and varieties of language. It defines language variation as differences in pronunciation, word choice, or grammar patterns among speakers. Variations can occur at geographical, social, stylistic, or functional levels. There are also three main levels of variation: pronunciation, grammar, and vocabulary. The document then defines and provides examples of several varieties of language, including standard languages, national/official languages, dialects, registers, pidgins, creoles, classical languages, lingua francas, and diglossia.