Shelta is a language spoken by Irish Travellers, particularly in Ireland, but also parts of Great Britain. It is widely known as the Cant, to its native speakers in Ireland as Gammon and to the linguistic community as Shelta. It was often used as a cryptolect to exclude outsiders from comprehending conversations between travellers, although this aspect is frequently over-emphasized. The exact number of native speakers is hard to determine due to sociolinguistic issues but Ethnologue puts the number of speakers in Ireland at 6,000, and 86,000 worldwide.

Linguistically Shelta is today seen as a creole language that stems from a community of travelling people in Ireland that was originally predominantly Irish Gaelic 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 and Gaelic. As different varieties of Shelta display different degrees of anglicization (see below), it is hard to determine the extent of the Irish/Gaelic substratum but the Oxford Companion to the English Language puts it as 2,000–3,000 words.