Manx is a form of Gaelic, very similar to Irish and Scottish.  The Irish Celts brought the language with them in the 5th century when they arrived along with Christianity.  In 1405 Henry IV of England gave the island to Sir John Stanley and the island was cut off from other Gaelic nations.  Although the populace continued to speak Manx, all documents were in English or Latin.  The big blow to the language  was tourism in the 20th century and Manx died along with the last native speaker, Ned Maddrell in 1974.  Or so people thought...

Fortunately for Manx, a revival had already begun in the 1960's and continued efforts of various organizations have brought the language back from the brink of extinction.  The map below is from the 2011 IOM census.  Click to be taken to the document.

Learn more of the language through LearnManx.com and their corresponding YouTube channel.