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.
Suibne mac Cináeda
The Gaelic "Gaidheal" (plural "Gaidheil") is primarily a linguistic term referring to speakers of Gaelic. The Gaelic term "Gall Gaidheil", literally meaning "Stranger-"Gaidheil"", first appears on record in the mid-ninth century. At this period in time, the term "Gall" (plural "Gaill") referred to Scandinavians, which indicates that "Gall Gaidheil" should be taken to mean "Scandinavian-"Gaidheil"". The term appears to have been applied to a population of mixed Scandinavian and Gaelic ethnicity in the Hebrides and part of the former kingdom of Dál Riata. The leader of the "Gall Gaidheil" in the mid part of the century appears to have been a certain Caittil Find—possibly identical to Ketill Flatnefr of Scandinavian saga tradition—who may have been seated in the Hebrides. If the little that is known of Caittil and his connection with the "Gall Gaidheil" is correct, it could be evidence that Suibne was a Hebridean chieftain as well.