This document discusses the concepts of language, dialects, and varieties from a sociolinguistic perspective. It defines varieties as sets of linguistic items with similar distributions. Languages can refer to single norms or groups of related norms, and dialects refer to individual norms within a language. Seven criteria are identified for distinguishing language types: standardization, vitality, historicity, autonomy, reduction, mixture, and de facto norms. Regional dialects vary based on geography in terms of pronunciation, vocabulary, and syntax. Social dialects originate from social groups and factors like social class, religion, and ethnicity. Registers are vocabularies associated with occupational or social groups. The document concludes that humans can comprehend many more language varieties than they can productively control