History of Scottish Gaelic
All surviving dialects are Highland and/or Hebridean dialects. Dialects of Lowland Gaelic have become defunct since the demise of Galwegian Gaelic, originally spoken in Galloway, which seems to have been the last Lowland dialect and which survived into the Modern Period. By the 18th century Lowland Gaelic had been largely replaced by Lowland Scots across much of Lowland Scotland. According to a reference in "The Carrick Covenanters " by James Crichton, the last place in the Lowlands where Scottish Gaelic was still spoken was the village of Barr in Carrick: only a few miles inland to the east of Girvan, but at one time very isolated. Crichton gives neither date nor details.
Languages of Northern Ireland
The Irish language (), or "Gaelic", is a native language of the island of Ireland. It was spoken predominantly throughout what is now Northern Ireland before the Ulster Plantations in the 17th century and most place names in Northern Ireland are anglicised versions of a Gaelic name. Today, the language is associated with Irish nationalism (and thus with the Catholic community). However, in the 19th century, the language was seen as a common heritage, with Ulster Protestants playing a leading role in the Gaelic revival.