Do you not use the 'n befor eisiau specifically? As I thought verbs usually were preceded by 'n
So how does "nac ydw" translate exactly? Looks like "neither yes" but I'm not sure.
Different forms of "yes/no" are used in different situations - in response to questions beginning with "ydych", e.g. "(y)dych chi eisiau reis?" you use the "ydw" form, which on it's own would mean something like "I am" or "I do". "Na" is a less specific word for "no", and so in front of "ydw" makes it negative. "Nac ydw" = "I don't" or "I'm not", depending on the question :)
No I do not I want rice. Was my only correct answer... I guess this is a mistake