"Oidhche mhath, a Sheumais."
Translation:Good night, James.
Oh, that's fabulous! My dad's given name was James, but all his life he was addressed as Hamish, to the point where people gave him handkerchiefs embroidered with "H" and pedantic little me thought, no that's not right, we only call him Hamish, his name's James. He did explain it to me, but nevertheless my mother and other relations still called him Hamish even when they weren't addressing him directly. (They were lowlanders though. And anyway by that time Hamish was his pet name.)
But this is the first time I've actually heard Seumas turn into Hamish.
(He actually told me they called him "The Hamish" in his youth in the Gaeltachd, but I don't entirely get that. He was the first generation of the family brought up without the Gaelic, so I'm giving it a shot.)
It's relatively common for native Gaelic speakers (and I mean ones whose first language is Gaelic, as opposed to native bilinguals) to add "the" to words in English which wouldn't normally have them. For example they would call Gaelic "the Gaelic" as opposed to just Gaelic, because that's what the name means in Gaelic.