No, of course I haven't, uh... Donna...?
But I hardly even knew ye!
What’s with the angh- part?
An=negative prefix that causes a nasal mutation. C mutates nasally to ngh so "Anghofio". One of the "n"s is dropped in this instance. Another example is An+Teg(fair)=Annheg(unfair), in this instance both the "n"s are kept.
Because without it cofio means "remember"!
an (negative prefix) + nasal mutation + cofio (to remember) = anghofio (to forget).
Why is 'did you forget me' incorrect?
Because that's a different tense. I don't know, but I would imagine that that would be something like "Anghofioch chi fi?", but I don't know as I'm still learning.