Does Gáidhlig agad -- have Gaelic -- mean speak Gaelic? To have Gaelic makes it sound like a store commodity to me.
It does indeed mean ‘to speak’. To ‘have’ a language is a common English phrase in areas of the Gaelic countries, no doubt influenced by the Gaelic construction.
Tá Gaelige agam,...I have Gaelic. To "have" it means you will have it always , whereas to speak merely means you are speaking it now. The Gaelic languages are part of one's heritage and birthright and that's why you "have" them.