"What should I have done?"
Translation:Beth ddylwn i fod wedi wneud?
So... if I understand correctly, one always need a form of 'bod' in a past tense construction with 'wedi', am I right? And why is 'wneud' mutated here? I thought 'wedi' didn't trigger any mutation.
First: Only with conditional verbs of that sort of short-form past tense pattern (I would have liked to have done this, I should have done that, etc):
- Dylai fe fod wedi mynd allan - He should have gone out.
- Hoffwn i fod wedi gwerthu fy hen gar cyn y gwyliau - I would have liked to have sold my old car before the holidays.
Second: gwneud needs an object, so we give it a notional ei (ei wneud, its doing) if there isn't one already:
- Dylwn i fod wedi('i) wneud - I should have done (it).
- Dylwn i fod wedi gwneud cadair newydd - I should have made a new chair.
I believe the mutation comes from an ei which is usually omitted in speaking but leaves behind its mutation -- you'll find it in other sentences with Beth as well, e.g. Beth mae o'n hoffi wneud yn ei amser sbâr? "What does he like to do in his spare time?".
So a bit more literally, I think it is/used to be "What does he like to do it" and "What should I have done it".
Thanks for the very quick reply and the explanation! These omitted particles make it very hard to use the correct mutations in the right place.
I remember wondering why we say ...ac mae... "...and...is..."; apparently that's due to a magical disappearing particle as well (from an original ac y mae or something like that).