"Sioned is beautiful in her wedding dress."
Translation:Mae Sioned yn brydferth yn ei ffrog briodas.
I am confused about this sentence.Why is it not"Mae Sioned yn brydferth yn ei ffrog briodas hi?".but both are fine
The possessive pronoun 'her' = ei...........hi
But the second part is often only used for emphasis.
Thus 'ei ffrog' = her dress
'ei ffrog hi' = HER dress
Why is the translation not "Mae Sioned yn brydferth yn ei ffrog briodas hi"?
Both are fine. The "hi" is omitted a lot nowadays, and I personally would never put it in if I was using an adjective (it isn't incorrect to I just personally wouldn't).
why is it wrong using yw instead of yn used twice , like "mae Sioned yw brydferth yn ei ffrog briodas "
Because they're not the same thing. "Yw" and "Mae" are both forms of bod, whereas "Yn" is what's called an "Ategydd berfol" which is used to connect forms of bod which come at the start of sentences (i.e "Mae" but not "yw") to a noun, verbnoun or adjective.