Regional variances (differences) in the same language are known as a Language branch
Language group
Language family
Language dialect
Language pidgin

Language dialect

Explanation:

Dialects are the variations of one language usually differentiated by the regions. Different dialects are part of the same language and most likely all the speakers of the language will understand each other.

The dialects will most likely differ in speech patterns, so the words and parts of grammar will be different than in the literate, “official” language.

Dialects are most often coming from groups living on different territories and in different regions, getting the characteristics of their local pattern of speech. However, some variants of language and dialects come from the class, educational or occupational variables.