Difference between Irish and Scot Gaelic

[Old Hippie]

I'm curious as to what differences there are in Irish and Scot Gaelic.

I used to fence with a guy from Ireland, when I lived in Iowa. Occasionally we'd try out bits of The Gaelic on each other -- he learnt his Irish Gaelic at the point of a nun's ruler, I have picked up a few phrases of Scottish Gaelic here and there. We found that we were unable to communicate. His wife was Italian; she understood neither of us.

He told me that in Ireland they say they speak Gaelic and the Scots speak "Erse", while the Scots I asked say that they speak Gaelic and the Irish speak "Irish."

That may not be helpful, but may define the scope of the question.