【Dialect】 , 【vernacular】 , 【patois】 , 【lingo】 , 【jargon】 , 【cant】 ,  【argot】 , 【slang】 denote a form of language or a style of speech which varies from that accepted as the literary standard.

【Dialect】 (see also LANGUAGE 1) is applied ordinarily to a form of a language that is confined to a locality or to a group, that differs from the standard form of the same language in peculiarities of vocabulary, pronunciation, usage, and morphology, and that persists for generations or even centuries.

It may represent an independent development from the same origin as the standard form (as the Sussex 【dialect】 ) or a survival (as the 【dialect】 of the Kentucky mountaineers). It is sometimes applied to any form of language differing from the standard.

【Vernacular】 (usually the 【vernacular】 ) has several applications, though it always denotes the form of language spoken by the people in contrast with that employed by learned or literary men.

In the Middle Ages when the language of the church, of the universities, and of learned writings was Latin, the 【vernacular】 was the native language of the people whatever it might be in the locality in question.

When a contrast with the literary language rather than with Latin is implied, the 【vernacular】 is an underogatory designation for the spoken language, the language that represents the speech of the people as a whole, that is colloquial but not inherently vulgar, and that is marked chiefly by the spontaneous choice of familiar, often native as opposed to exotic words and phrases.

【Vernacular】  often implies a contrast with scientific nomenclature.

【Patois】 is often used as if it were the equivalent of 【dialect】 . It tends, however, to be restricted especially in North America to designating a form of speech used by the uneducated people in a bilingual section or country; the word often specifically refers to the hybrid language (of mingled English and Canadian French) spoken in some parts of Canada.

【Lingo】 is a term of comtempt applied to any language that is not easily or readily understood. It is applicable to a strange foreign language, a 【dialect】 , or a 【patois】 or to the peculiar speech of a class, cult, or group.

【Jargon】 , which may be applied to an unintelligible or meaningless speech (as in a foreign tongue or a 【patois】 ), is used chiefly in reference to the technical or esoteric language of a subject, a class, a profession, or a cult and usually expresses the point of view of one unfamiliar with it and confused or baffled by it.

【Cant】 , related to chant, seems to have been applied first to the whining speech of beggars. It has been applied more or less specifically to several different forms of language (as the secret language of gypsies and thieves, the technical language of a trade or profession, and the peculiar phraseology of a religious sect or of its preachers).

From the last of these applications a new sense has been developed (see HYPOCRISY). When referring to the peculiar language of a subject or profession 【cant】 usually suggests the hackneyed use of set words or phrases, often in a specialized sense, and, unlike 【jargon】 , does not usually imply unintelligibility; thus, the language of sportswriters is a 【cant】 rather than a 【jargon】 ; the scientific nomenclature used by physicians in official reports may be called medical  【jargon】 rather than 【cant】 by those who do not understand it; a person who repeatedly calls an investigation a "probe," a large book a "tome," a preacher a "parson," or his wife "my better half" may be said to be given to 【cant】 .

【Argot】 is applicable chiefly to the 【cant】 of the underworld; it is now sometimes used of any form of peculiar language adopted by a clique, a set, or other closely knit group.

【Slang】 does not as often denote a form of language or a type of speech as it does a class of recently coined words or phrases or the type of word which belongs to that class.

【Slang】 implies comparatively recent invention, the appeal of the words or phrases to popular fancy because of their aptness, picturesqueness, grotesqueness, or humorousness, and usually an ephemeral character.