This seems to be a good-going thread, so I thought I would join in!
I had ancestors in Kelso called Stewart, and for a long time I was content to have traced them back to the early 1700s, but then I took a notion to try and push the family-tree back a bit further. The Kelso records are very full, and I soon managed to get back to a James Stewart and Nanc Companion who were married there in 1609. Nanc or Nans is a short form of Nancy, often used in Scotland for Agnes.
Companion is an unusual surname, and when I checked on Scotlandspeople I found that it's very rare in Scotland, disappearing here after the death of Barbara Companion in Montrose in 1740. But then I googled it and found that Compagnon is a common surname in France and both Compagnon and Companion are common in French Canada. So I suspect that those Companions in Scotland were Huguenots. Nanc Companion may have started as an Agnès Compagnon.
Of course, there were French-speakers in Scotland long before the Huguenots, by which I mean the Anglo-Norman aristocracy and their followers who were invited up here by King David I in the 12th century. It's well known that many Scottish surnames like Fraser, Gordon, Bruce, Hay, Melville, Lessels etc. are of French origin. What is not so easy to establish is whether or not a modern Fraser or Bruce is directly descended from a Frenchman of that name, or from an ordinary peasant who adopted the laird's name when surnames became compulsory for taxation purposes. The new science of genetic genealogy (which starts with a simple cheek swab!) has been applied to some of the Highland clans and on average between 20% and 30% of McDonalds, McKenzies etc. tested turn out to be genetically related to the current clan chief who bears their surname.
I also had ancestors called Pettigrew who were Ulster Presbyterians in the Belfast area, and who moved to Scotland in the 1830s. I suspect their ancestors were Scots. Pettigrew or Petticrew is a very old name in Lanarkshire, and seems to be from French 'petit' and 'cru', "small growth", maybe a nickname for a small man, like Tiny or Shorty. My research into the Pettigrews in medieval Scotland has shown a strong pattern of connection and relationship to the Hamiltons, the feudal lords of Lanarkshire, who themselves were Anglo-Normans. I suspect (I'm always suspecting!) that they brought the Pettigrews with them to Scotland in their wake.
Harry