Definition -
(1) A form of speech that is peculiar to a region or to a specific group of speakers.
(2) A subordinate version of a language that has non-standard pronunciation, grammar, or vocabulary.

Example -
Standard American English, Standard British English, and Standard Indian English are all standard dialects of the English language.

Etymology -
The word derives via Middle French from the Latin dialectus, local language or way of speaking; ultimately it derives from the Greek dialegesthai, converse with each other (from dia, between + legein, speak).

Oxford English Dictionary -
Its first citation is from 1579:
"Neither … must … the common Dialect and manner of speaking [be] so corrupted thereby, that [etc.]."
(E. K. Ded. to Spenser's Sheph. Cal.)

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