Different forms of yes/no
First off, I'm really enjoying this course a bunch - always wanted to learn Welsh, but was unfortunately cursed to an English language school when I was younger.
Secondly, I keep getting confused between which form of yes or not to use in different cases, it would be useful if this could be clarified somewhere in the course.
This causes a heck of a lot of confusion, even amongst some "first" language speakers sometimes. The thing is, any yes and/or no is linked to the tense. So any that start with "dych chi/wyt ti" will be "ydw/nac ydw"; any with "oes" will be "oes/nac oes"; any with "fydd" would be "bydd"; any with "oedd" would be "oedd, roedd.....".
Confusing, yes; impossible, no (see what I did there? :P)
They get easier as time goes by (or you can just say wrth gwrs! (of course) or na, siŵr! (of course not!), hahaha).
I've been wondering the same. This explanation on wikibooks seems pretty good: https://en.wikibooks.org/wiki/Welsh/Useful_Phrases#Yes_and_No
The thing with yes/no in Welsh (and all Celtic languages) is that there is no one word for it. Instead of saying yes/no you repeat the verb used in the question. So if the question is 'Dych chi ....?' (2nd plural/polite you of the verb bot 'to be') you answer 'ydw/nac ydw' (1st singular of the verb to be). For example: Do you wear shoes?: Dych chi'n gwisgo esgidiau? (lit. Are you in wearing shoes?) 'Ydw/Nac ydw (I am/I am not).
I don't know how far you are in the tree (and tbh I'm not that far yet so I don't know when verbal forms will be introduced), but Welsh uses a lot of periphrasis, so the verb used most often is the verb 'to be' (which is also one of the few irregular verbs, as in many languages).
If a different verb were to be used in a question, you'd answer yes/no using that verb. It's been over half a year since I did Welsh last, so I can't think of another verb that isn't another irregular one (or the Middle Welsh form...). I'm not a native speaker, so I don't know if you'd be able to use ydw/nac ydw when a different verb was used in the question in colloquial speech. I think you can in Irish at least, so maybe in Welsh too. And you'd probably get away with just using the English yes/no.
When I'm struggling through Welsh in real life, I normally just do Ie/Na for everything, but I've no idea how right that is, but I remember my Welsh teacher in school having a big grid of about 5 or 6 different yes/no's on the wall.
That's interesting though, what you said about verbs, I'll have to pay attention and see how often that happens further down the tree, because there's already yes/no's appearing I never learnt in school. Cheers!
I hope you are correct mennarempt because this is the clearest explanation of the variations of yes/no in Welsh that I've read. Was absolutely flummoxed by the time I reached Oes/Nac oes. It's a verb and a yes/no also? Could not and do not yet understand the logic of this yet but at least I know I am not hallucinating