Given the enormous social role of language, it is not surprising that much research in linguistics focuses on the role of language in society. Sociolinguists typically study language synchronically, or at a particular moment, rather than over historical periods, diachronically. Sociolinguists study language variation and the factors that affect it, but when they do so, they might be studying phonetics, phonology, morphology, syntax, or semantics of the language variety. All aspects of language can vary across dialects. Stereotypes and attitudes about language varieties exist for all languages everywhere. One could find Spaniards from Madrid criticizing the language of Spaniards from Seville. Sometimes the use of a particular language or dialect is carefully planned, with official governmental policies developed to ensure that the language is spoken and/or taught in schools. Language planning and policy arise out of socio-political situations where, for example, speakers of various languages compete for resources or where a particular linguistic minority is denied access to basic rights.