"May I have a cup of tea, please?"
Translation:Ga i baned, plîs?
I just get the answer 'ga i baned, plis?' - wouldn't that be 'May I have a cup?'
paned is the not the cup itself (the porcelain object) -- that would be a cwpan.
A paned is a "cuppa" -- that is, a cupful (quantity) of a substance. In context, that substance is essentially always tea or coffee.
paned is from cwpanaid -- cwpan : cwpanaid :: cup : cuppa
If you ask for 'a cuppa'/paned in Britain, it is generally assumed that you mean tea unless you specify something else. This is explained in the course notes.
To see how to get to the course notes, go to https://forum.duolingo.com/topic/924/hot and look for 'Course tips and notes'. The duome link there is useful for seeing all the notes in one place.