Variety of a language spoken by a group of people and having features of vocabulary, grammar, and/or pronunciation that distinguish it from other varieties of the same language.
Dialects usually develop as a result of geographic, social, political, or economic barriers between groups of people who speak the same language. When dialects diverge to the point that they are mutually incomprehensible, they become languages in their own right. This was the case with Latin, various dialects of which evolved into the different koine .