Individuals differ in the manner in which they speak their native tongue, although usually not markedly within a small area. The differences among groups of speakers in the same speech community can, however, be considerable. These variations of a language constitute its dialects. All languages are continuously changing, but if there is a common direction of change it has never been convincingly described. Various factors, especially the use of written language, have led to the development of a standard language in most of the major speech communities—a special official dialect of a language that is theoretically maintained unchanged.
This official dialect is the school form of a language, and by a familiar fallacy has been considered the norm from which everyday language deviates. Rather, the standard language is actually a development of some local dialect that has been accorded prestige. The standard English of England is derived from London English and the standard Italian is that of Tuscany. Use of the standard language is often a mark of polite behavior. In the United States employing standard English, which largely entails the usage of approved grammar and pronunciation, marks a person as cultivated. Ordinary speech may be affected by the standard language. Thus, many forms of expression come to be considered ungrammatical and substandard and are regarded as badges of ignorance, such as you was in place of the standard you were.
As in other fields of etiquette, there is variation. Gotten is acceptable in the United States but not in England. The literary standard may differ from the colloquial standard of educated people, and the jargon of a trade may be unintelligible to outsiders. Such linguistic variations in English are mainly a matter of vocabulary. An auxiliary language is a nonnative language adopted for specific use; such languages include lingua franca, pidgin, and international language.