This document discusses speech communities and speech varieties. A speech community is defined as a group that shares a language or language variety and whose members interact frequently. There are four main types of speech varieties: standard languages, social dialects, regional varieties, and registers. Standard languages are promoted varieties, while social dialects are defined by social attributes. Regional varieties are defined geographically and registers are defined by social context or situation. The document also discusses social differentiation of language and how socioeconomic status can correlate with differences in language use.