There are two languages of Pitcairn Island, English and Pitkern.
Pitkern is a creole language based on eighteenth-century English and Tahitian and spoken by about fifty people inland not to mention those outside Adamstown, mostly dozens of children leaving Pitcairn while becoming adults. It is partly derived from eighteenth-century English because Pitcairn Island was settled by the Bounty mutineers in the eighteenth century, and they brought some people from Taihiti with them.
Pitkern is closely related to Norfuk spoken on Norfolk Island, where some descendants of the mutineers subsequently settled.