Street signs in the Highlands / Middle Scotland

[Knight]

Hi--I recently returned from a ten day trip to Scotland. One of the things my wife and I noticed, to our surprise, was a great number of signs in what *appeared* to be Gaelic (based on our tiny handful of words from Outlander) on street, town, and advert signs throughout the middle and Highland areas of Scotland. The further north we went, the more we noticed it being used in print, though I don't recall anyone speaking it (I have a good ear for languages, being able to speak, read and write fluently in three, and read, write, and stutter in two more, and sign in a fifth, but admittedly I don't have more than a handful of words in Gaelic, so I may have overhead it and not realized it).

My question, for native Scots who might know or have some familiarity with the language, or with the initiative or program that led to the signs being "gael-ified" (gael-vanized? sorry...), is what form of Gaelic these signs are in. Is this the same as the Irish Gaelic being used in Ireland? Is it a variant of it? Is it interchangeable? My wife had decided she wanted to learn Irish Gaelic in advance of the trip, in preparation for a trip to Ireland. She's heavily Irish by descent and thought it would be cool. Being an hobbyist linguist, she asked for my help. Seeing Gaelic used on signs redoubled her interest, so I'm in for both the pound AND penny now. I noticed "Failte" written in several shops near Inverness (Inbhir Nis, per the train stop), which is "Welcome" in Irish, as far as I know. That got me wondering about how useful the Irish Gaelic we've been tinkering with would be on a return trip to the Highlands. I definitely want to go back; we had far too little time for such a gorgeous area.

I guess I'd really appreciate some clarification on what sort of Gaelic those signs were, and the degree of similarity to the modern Irish Gaelic. Any info would be gratefully received!