"What time does she want dinner?"
Translation:Am faint o'r gloch mae hi eisiau cinio?
Why would you use mae here and not ydy? Is ydy only used in yes/no-questions?
It depends on what the question is about.
Questions about how, when, where, why, how often, how quickly, etc, or which start with a preposition or an adverb are generally followed by mae - sut (how), pryd, ble/lle, pam, pa mor aml, pa mor gylfym, am beth, i bwy, gyda phwy, etc.
Am faint o'r gloch...? is asking when, so it is followed by mae.
- Sut mae Dewi heddiw? - How is Dewi today?
- Pa mor aml mae e'n dod yma? - How often does he come here?
- Ble mae e'n eistedd? - Where does he sit?
- Gyda phwy mae e'n eistedd? - With whom does he sit?
- Â phwy mae e'n siarad? - Who is he speaking to? (With whom is he speaking?)
- I bwy mae'r anrheg? - Who is the present for? (For whom is the present?)
The way one of my Welsh teachers explained it to me is that 'ydy' is used with a pronoun (pwy, peth) but 'mae' is used with other question words (ble, pryd, pam, sut, etc) since they're adverbs or, in the case of, 'am faint o'r gloch', a prepositional phrase.
moyn is "to want" or "wanting". Used especially in the south.
It's a normal verbnoun so it takes yn after dw i (etc.), unlike eisiau which does not.
So you could have dw i'n moyn mynd for "I want to go" or dw i eisiau mynd. (But not dw i'n eisiau mynd.)
No. You could use something like that if you wanted to know, say, how fast someone had run a race:
- Beth oedd ei hamser? 30 eiliad - araf iawn! - What was her time? 30 seconds - very slow!