What is the Latin word for dialect?

The usual Latin words for “dialect” are dialectos, sermō. The right choice depends on the sense; see the distinctions below.

English → Latin

“dialect” in Latin

dialectosa dialect (a form of a language peculiar to a region) (esp. Greek)sermōa conversation, discussion; a rumor, diction, speech, talk, discourse; a language, manner of speaking

The English word dialect itself goes back to Latin dialectos.

Riddle & Arnold A Copious and Critical English–Latin Lexicon, 1864

dialect

genus linguae: dialectus (the former the Latin expression, the latter borrowed from the Greek; Suet., Tiberius, 56). Earlier writers used lingua or sermo. The five Greek dialects, quinque sermonis Graeci differentiae. To speak in the Doric dialect, Dorice loqui.

Quick answer

What is the Latin word for dialect?: The usual Latin words for “dialect” are dialectos, sermō. The right choice depends on the sense; see the distinctions below.

Entry from J. E. Riddle & T. K. Arnold, A Copious and Critical English–Latin Lexicon (rev. C. Anthon, New York: Harper, 1864), digitised by Fergus J. P. Walsh, CC BY-SA 4.0; Latin markup adapted by latindictionary.co.