Been having 1/2 hour talks with a Welsh speaker ( from birth ) also using the OUP Modern Welsh Dictionary ( MWD ) to try to improve.
Got to talking about yw - which the MWD says is only used in South Wales in an interrogative form - but I think after talking with the Welsh speaker that this is just plain wrong e.g. ‘Fy hoff hobi Yoga yw e’ isn’t interrogative - but it is ok ? On’d yw e ?
I agree that limiting yw to the interrogative form is too restrictive, it can certainly be used in identification sentences such as Caerdydd yw prifddinas Cymru.
Here is answer from SSIW : You’re right about “yw”. It’s used in more places that just the interrogative form, but perhaps what the MWD meant is that “only in South Wales” is it used in interrogation, not in North Wales?
Your example would usually be “Yoga yw fy hoff hobi” which is called a ‘focused sentence’ in the grammar books, emphasizing that ‘Yoga’ is your favourite, not any of the other possible hobbies. Without that focus it would be the usual word order - “Mae yoga’n fy hoff hobi” - but that really doesn’t sound natural. In these cases, the focused order is much more common.
Another example would be “Car Siôn yw hwnna” - that car is Siôn’s.
Thanks Hendrik - Please see response I sent to John Young on this topic .
My understanding is John yw enw makes sense because John could be any number of different people. But Enw yw John makes no sense because Enw could not be anything else.