There are two main schools of thought on the origin of the word cant.
In Celtic linguistics, the derivation is normally seen to be from the Irish word caint (older spelling cainnt) "speech, talk". In this sense it is seen to have derived amongst the itinerant groups of people in Scotland and Ireland, hailing from both Irish/Scottish Gaelic and English speaking backgrounds ultimately leading to a creole language.
In the Scottish context, it has given rise to the terms Scottish Cant (a variant of Scots with Romani and Scottish Gaelic influences) and the Highland Traveller's Cant (or Beurla Reagaird), a Gaelic-based cant.
Within this derivation, the history of the word is seen to originally have refered to the chanting of friars in a disparaging way some time between the 12th and 15th century, then the singsong of beggars and eventually a criminal jargon.
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.
In June 2009 it was reported that inmates in one English prison were using "Elizabethan Cant" as a means of communication that guards would not understand, although the words used are not part of the canon of recognised cant.
The word was 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.
Cant words that have been adopted by mainstream English include words such as: