Scots got their Gaelic from an Irish kingdom
The Gaelic language originally came to Scotland circa 500AD with the expansion of the Irish kingdom of Dál Riata (North Antrim) into the Western Isles and Highlands of Scotland.
The expansion of the language was aided no end in the conversion process of various tribes by the Irish monastic settlement of Iona headed initially by Columcille and his followers who converted much of north Britain.