Hi all,
Similar to this post by Joshua, I also grew up in South Wales (Cardiff) learning ‘my’ for ‘mae’, ‘Cymr-eye-g instead of Cymraag’. Having found that post, it has cleared it up for me somewhat (though I probably shouldn’t have waited til the end of level 3 to look it up).
What I do find confusing for learners though, is that Cat and Iestyn seem to pronounce them differently, and sometimes differently from themselves! For example, in one of the last lessons, Iestyn says camgymeriadau with ‘eye’ on the end, and then shortly afterwards, with ‘ah’ on the end.
I guess my question is, how do other people overcome this confusion when hearing words a certain way is how we learn to prounounce them, resulting in accents. When we hear two versions every time we hear a new word, what do we do? I suppose the answer will be, don’t worry and just see which one tends to roll off my tongue, won’t it? 
