A cant is the jargon or language of a group, often employed to exclude or mislead people outside the group. It may also be called a cryptolect, argot, pseudo-language, anti-language or secret language. Each term differs slightly in meaning; their use is inconsistent.
There are two main schools of thought on the origin of the word cant:
An argot (English: //; from French argot [aʁɡo] 'slang') is a language used by various groups to prevent outsiders from understanding their conversations. The term argot is also used to refer to the informal specialized vocabulary from a particular field of study, occupation, or hobby, in which sense it overlaps with jargon.
In his 1862 novel Les Misérables, Victor Hugo refers to that argot as both "the language of the dark" and "the language of misery."
The earliest known record of the term argot in this context was in a 1628 document. The word was probably derived from the contemporary name les argotiers, given to a group of thieves at that time.
Under the strictest definition, an argot is a proper language with its own grammatical system. Such complete secret languages are rare because the speakers usually have some public language in common, on which the argot is largely based. Such argots are lexically divergent forms of a particular language, with a part of its vocabulary replaced by words unknown to the larger public; argot used in this sense is synonymous with cant. For example, argot in this sense is used for systems such as verlan and louchébem, which retain French syntax and apply transformations only to individual words (and often only to a certain subset of words, such as nouns, or semantic content words). Such systems are examples of argots à clef, or "coded argots".
Specific words can go from argot into common speech or the other way. For example, modern French loufoque 'crazy, goofy', now common usage, originates in the louchébem transformation of Fr. fou 'crazy'.
In the field of medicine, physicians have been said to have their own spoken argot, cant or slang, which incorporates commonly understood abbreviations and acronyms, frequently used technical colloquialisms, and much everyday professional slang (that may or may not be institutionally or geographically localized). While many of these colloquialisms may prove impenetrable to most lay people, few seem to be specifically designed to conceal meaning from patients (perhaps because standard medical terminology would usually suffice anyway).
The concept of the anti-language was first defined and studied by the linguist Michael Halliday, who used the term to describe the lingua franca of an anti-society. He defined an anti-language as a language created and used by an anti-society. An anti-society is a small, separate community intentionally created within a larger society as an alternative to or resistance of it. For example, Adam Podgórecki studied one anti-society composed of Polish prisoners; Bhaktiprasad Mallik of Sanskrit College studied another composed of criminals in Calcutta.
Anti-languages are developed by these societies as a means to prevent outsiders from understanding their communication, and as a manner of establishing a subculture that meets the needs of their alternative social structure. Anti-languages differ from slang and jargon in that they are used solely among ostracized social groups including prisoners, criminals, homosexuals, and teenagers. Anti-languages use the same basic vocabulary and grammar as their native language in an unorthodox fashion. For example, anti-languages borrow words from other languages, create unconventional compounds, or utilize new suffixes for existing words. Anti-languages may also change words using metathesis, reversal of sounds or letters (e.g. apple to elppa), or by substituting their consonants. Therefore, anti-languages are distinct and unique, and are not simply dialects of existing languages.
In his essay "Anti-Language", Halliday synthesized the research of Thomas Harman, Adam Podgórecki, and Bhaktiprasad Mallik to explore anti-languages and the connection between verbal communication and the maintenance of social structure. For this reason, the study of anti-languages is both a study of sociology and linguistics. Halliday's findings can be compiled as a list of nine criteria that a language must meet to be considered an anti-language:
Examples of anti-languages include Cockney rhyming slang, CB slang, verlan, the grypsera of Polish prisons, thieves' cant, Polari, and possibly[weasel words] Bangime.
Anti-languages are sometimes created by authors and used by characters in novels. These anti-languages do not have complete lexicons, cannot be observed in use for linguistic description, and therefore cannot be studied in the same way that a language that is actually spoken by an existing anti-society would. However, they are still used in the study of anti-languages. Roger Fowler's "Anti-Languages in Fiction" analyzes Anthony Burgess's A Clockwork Orange and William S. Burroughs' Naked Lunch to redefine the nature of the anti-language and to describe its ideological purpose.
A Clockwork Orange is a popular example of a novel in which the main character is a teenage boy who speaks an anti-language called Nadsat. This language is often referred to as an argot, but it has been argued that it is an anti-language because of the social structure that it maintains through the social class of the droogs.
In parts of Connacht in Ireland, Cant mainly refers to an auction typically on fair day ("Cantmen and Cantwomen, some from as far away as Dublin, would converge on Mohill on a Fair Day, ... set up their stalls ... and immediately start auctioning off their merchandise") and secondly means talk ("very entertaining conversation was often described as 'great cant'" or "crosstalk").
In Scotland, two unrelated creole languages are termed as "cant". Scottish Cant (a mixed language, primarily Scots and Romani with Scottish Gaelic influences) is spoken by Lowland Roma groups. Highland Traveller's Cant (or Beurla Reagaird) is a Gaelic-based cant of the Indigenous Highland Traveller population. The cants are mutually unintelligible.
The word has also been used as a suffix to coin names for modern-day jargons such as "medicant", a term used to refer to the type of language employed by members of the medical profession that is largely unintelligible to lay people.
The thieves' cant was a feature of popular pamphlets and plays particularly between 1590 and 1615, but continued to feature in literature through the 18th century. There are questions about how genuinely the literature reflected vernacular use in the criminal underworld. A thief in 1839 claimed that the cant he had seen in print was nothing like the cant then used by gypsies, thieves and beggars. He also said that each of these used distinct vocabularies, which overlapped, the gypsies having a cant word for everything, and the beggars using a lower style than the thieves.
Ulti is a language studied and documented by Bhaktiprasad Mallik in his book Languages of the Underworld of West Bengal. Ulti is an anti-language derived from Bengali and used by criminals and affiliates. The Ulti word kodān 'shop' is derived from rearranging the letters in the Bengali word dokān, which also means 'shop'.