As "gweld" is "to see" is it necessary to place "i" in front of weld? Should it be "Aeth hi gweld yr athro" instead of "Aeth hi i weld yr athro" ?
i is required here.
mynd i (wneud rhywbeth) - going to (do something). The i here is used to add the meaning of purpose to mynd - going in order to do something:
- mynd i weld - going to see
- mynd i wneud - going to do
- mynd yno i brynu car - going there to buy a car