Why the extra 'a' before ólann? Anyone?
It's a marker for the relative clause, and is required after question words (Same a as in Conas atá tú). Literally, the sentence is "Who is it, that drinks mils?" There's an implied copula (is) within the cé.
Thanks for the explanation. Sorry to be slow to get it, but where is the 'a' in Conas atá tú? ? I think I understand the rest of your explanation.
a tá. They're just written together
Got it now. Tks!