"Byddwn i'n bwyta cacen gaws."
Translation:I would eat cheesecake.
No. There are two main stems used in the conditional in the colloquial language - bydd- and bas-:
- Byddwn i = Baswn i - I would be
- Byddet ti = Baset ti - You would be
In the colloquial language they are equivalent in meaning. In your own use of the language, pick one stem and stick with it, just to keep things simple and consistent. If you are in Wales, just listen/look out for which stem people around you are using and use that. There are some other variations of the stems but the endings are the same:
- -wn, -et, -ai, -en, -ech, -ent.
(Note that in some dialects the pronunciation of the endings may change a little.)