Why is it necessary?maybe if i know ill stop forgetting
According to this, it's when it's your (her, their, his, whosever) portion of something.
The other time it's used is for uncountable (which I assume is the same as collective) nouns.
I think 'cuid' is normally used for mass nouns
This may be a dumb question, but if it were "his Irish" or "their Irish" or something like that, would it be "a chuid" and "a gcuid" etc or does cuid not work like that?
That's exactly how it would work:
a chuid Gaeilge - "his Irish"
a cuid Gaeilge - "her Irish"
a gcuid Gaeilge - "their Irish"
Shouldn't cuid be in the genitive case (coda) or is this a double genitive situation, in which case, shouldn't it be lenitied?
Should "cuid" (or "chuid") be used here? "Tá sí ag cleachtadh a cuid Gaeilge"
Yes. cuid is necessary herr
Because language is uncountable?
I already used "cuid" with the name of a language and got it wrong. So when do you use it ( except for unaccountable words, of course)