I wrote, 'Do you want a potato?', and was marked wrong. - Is 'tatws' only plural?
Tatws is the plural and taten us the singular.
Can this be translated as "Do you want potato?" in the same way that "Dych chi eisiau bresych?" can be translated as "Do you want cabbage?"?
I'm guessing tattws is why us Welshies call them "tatties".