Hi.
Not always sure about Welsh for the English word “have”. Understand “mae gen i gath” for I have a cat. And “mae gen i cwestiwn” for I have a question. And “dw i’n cael cinio” or “dw i’n cael amser da” for I’m having dinner or I’m having a good time.
But not sure why, if it’s “dw i’n cael cinio”, it’s not “dw i’n cael cwestiwn”.
Anyone help??
Andy
The underlying problem here is that the english word “have” is rather overloaded (although you don’t necessarily notice this as an experienced speaker, unless you make a conscious effort to do so), and as such there isn’t a 1-to-1 translation to Welsh that would cover all meanings.
The “gen i” construction is for things you already have or own (I have a car), but cael is used when you receive or acquire something (I’ll have a sandwich for lunch. I had a good time.)
I always found it useful to think of cael as get rather than have. Doesn’t have(!) a 100% equivalence, but it makes you think twice before using it incorrectly.
BTW, if you do inadvertently say something like dwi’n cael cwestiwn, people will understand, even if it sounds a bit strange, so there’s no need to stop the conversation in its tracks and correct yourself. Just move on and learn from it!
Diolch, Hendrik a Rob. I think I understand better. So I could say “Mae gen i frechdan, felly dw i’n mynd i cael brechdan am ginio” (I have a sandwich, so I’m going to have a sandwich for lunch)?
yup, spot on! 
Diolch, pawb!
Another good question with useful answers, thanks everyone!