There it is. This is the only form of 'no' I ever heard or used, growing up.
The correct use of this form of 'no' is in response to a question that doesn't start with a verb.
eg, Sioned dych chi? (are you Sioned?) - Nage, Siân dw i (No, I'm Siân)
Otherwise the form of 'no' used depends on the verb.
Right. I think my experience is a function of being chwe oed when I last spoke welsh. I seem to have learned only the emphatic question structure, and a huge number of rural idioms, during that time... thanks!
Huge number! I urge you to write those down somewhere as I'm sure many would like to read them