I see the usage ‘Bu farw’ and ‘Bu fyw’, rather than ‘bu’n farw’ or ‘buodd yn farw’ or whatever.
Can this construction be used with other verbs? “Bu oroesi”? Can it be used with other persons? Buom oroesi? (or something like?)
Diolch pobl garedig!
This is a preterite form of bod which rarely gets used in speech other than things like formal news-type reports. It’s usually conjugated as
and these can be used with other verbs e.g. buon nhw’n ymarfer trwy’r bore
But the ‘bu’ form ( a special type of 3rd person singular) is even more rarely heard other than in literary use or a few common select phrases (such as the ‘bu farw’ you mentioned).
Seren ydych chi, Siaron! Diolch unwith eto.