Hello Nina, A dialcet* is a form of a language spoken in a particular geographical area or by members of a particular social class or occupational group, distinguished by its vocabulary, grammar, and pronunciation. It could also refer to an inferior form of language. It is kind of an accent, lingo ,jargon or localism. Slang* consists of words, expressions, and meanings that are informal and are used by people who know each other very well or who have the same interests.It includes mostly expressions that are not considered appropriate for formal occasions; often vituperative ( marked by harsh abusive criticism ) or vulgar.

dialect 1.The usage or vocabulary that is characteristic of a specific group of people. "the immigrants spoke an odd dialect of English"; "it has been said that a language is a dialect with an army and navy" slang 1.Informal language consisting of words and expressions that are not considered appropriate for formal occasions; often vituperative or vulgar "their speech was full of slang expressions" cowboy...

Slang is the use of highly informal words and expressions that are not considered standard in the speaker's dialect or language. Slang is often very colloquial and tends to be specific to a particular territory. Slang terms are frequently particular to a certain subculture and members of a minority, but some terms may spread out of the original boundaries and become fashionable too. Note that slang is different to jargon, the technical vocabulary of a particular profession.