[4] It is widely known as the Cant, to its native speakers in Ireland as de Gammon or Tarri, and to the linguistic community as Shelta.
[6] Linguistically Shelta is today seen as a mixed language that stems from a community of travelling people in Ireland that was originally predominantly Irish-speaking.
The community later went through a period of widespread bilingualism that resulted in a language based heavily on Hiberno-English with heavy influences from Irish.
[5] As different varieties of Shelta display different degrees of anglicisation, it is hard to determine the extent of the Irish substratum.
People outside the Irish Traveller community often refer to it as [the] Cant, the etymology of which is a matter of debate.
[8] The word Shelta appeared in print for the first time in 1882, in the book The Gypsies by the "gypsiologist" Charles Leland, who claimed to have discovered it as the "fifth Celtic tongue".
Modern Celticists believe that Irish siúl [ʃuːlʲ] "to walk" is at the root, either via a term such as siúltóir [ˈʃuːl̪ˠt̪ˠoːɾʲ] 'a walker' or a form of the verbal noun siúladh, cf.
[5] Celticist Kuno Meyer and Romani expert John Sampson both assert that Shelta existed as far back as the 13th century.
Most Gammon words were formed from Irish by applying four techniques: reversal, metathesis, affixing, and substitution.
Some of the more frequently prefixed sounds were s, gr, and g. For example, obair, 'work or job', became gruber in Gammon.
But many early Celtic scholars who studied it, including Kuno Meyer, concluded it was much older.Thus, by design, it is not mutually intelligible with either English or Irish.
Additionally, [ey, iy, ow, uw] can be realized as diphthongs in certain varieties of Shelta.
Both versions are adapted from Hancock[20] who notes that the Cant reproduction is not exactly representative of actual speech in normal situations.