Why was dw i menyw wrong?
Because we use the emphatic semtemce form sentences like this.
Difference between Gwraig, Dynes, Menyw as far as dialects go?
Menyw is SW
Dynes (usually pronounced dynas) is NW
Gwraig is a bit old fashioned since it using the word for 'wife' for 'woman' and was fairly widespread I think, less so now.
Ive been a welsh speaker all my life and never heard of menyw - dynes is what i know (can you spot im from north wales?!). It'd be helpful to have dynes here as well.
"Dynes dw i" was accepted.