What is a dialect?
A dialect is a form or variety of a language, which usually refers to regional speech, but can extend to cover differences according to class and occupation. There are class dialects, occupational dialects, regional dialects, rural dialects, social dialects, urban dialects, etc. There are also distinct varieties of language spoken by an individual or group, such as acrolet (a prestigious dialect), basilect (a socially stigmatized dialect), or mesolect (a dialect that it socially in the middle). Most languages have dialects – each with a distinctive grammar, idiom, morphology, phonology/pronunciation, syntax, and vocabulary. Dialects have typically been regarded as socially lower than the standard or formal form of the language. Philologists and dialectologists regard a dialect as an historical subordinate of a language, and a language as the aggregate of the dialects. Dialects are often studied and described as an evolution and their distribution is studied.
[–M.C. + M.R.] A dialect is any variety of a language spoken by a specific community of people. Most languages have many dialects. Everyone speaks a dialect. In fact everyone speaks an _idiolect_, i.e., a personal language. (Your English language is not quite the same as my English language, though they are probably very, very close.) A group of people with very similar idiolects are considered to be speaking the same dialect. Some dialects, such as Standard American English, are taught in schools and used widely around the world. Others are very localized. Localized or uneducated dialects are _not_ merely failed attempts to speak the standard language. William Labov and others have demonstrated, for example, that the speech of inner-city blacks has its own intricate grammar, quite different in some ways from that of Standard English.