Two quick ones:
1) I was thinking about what they say about breadmaking "The wetter, the better" and realised I wasn't too sure how to do those "the...the..." structures in Welsh. I thought of "Wlypach ydy well, medden nhw," but I'm also thinking that there's something like "cyn mor...cyn mor..." or something like that?
2) If I wanted to emphasis what I was doing, instead of saying just O'n i'n siarad Cymraeg neithiwr, would it be Siarad Cymraeg o'n i'n, neithiwr, or Yn siarad Cymraeg o'n i, neithiwr? I'm torn between feeling the first one sounds OK and feeling that they're both a bit weird. In support of the first one I'm sure I've heard something like mae o yn as a complete clause, in contexts where you might say in English, say, "You told me he doesn't like cricket, but he does."