- Nac ydw = "No (I don't / I am not)"
- Nac ydy = "No (he doesn't / he isn't)"
(or "she" or "it" instead of "he", of course.)
Without context, is there a way I should be telling the difference between "he/she" in this question? The same with "Nac Ydyn"... How do I tell if it's "we" or "they" without having the other words like "e/o" or "hi", and "ni" or "nhw" following it?
Because of the context. Just like in this case you can't tell if "nac ydy" refers to "he" or "she", without a question you can't know if "nac ydyn" refers to "we" or they".
Because ydy is used in the 3rd person so it can be either he/she/it I think.
I think it's because 'nac ydy' could mean 'it is not' 'she is not' or 'he is not' depending on the context of the question. So writing 'it is not' isn't wrong, but it's being over-specific. I'd just stick to 'Nac ydy' meaning 'no', unless you have the question along with it, then that allows you to be more specific : )