"Ydy e'n gallu canu?"
Translation:Is he able to sing?
Thank you both, ibisc and rmcode, for these helpful answers. I am ashamed that the query was a month ago and I have not commented since. Outside life caught up with me, getting certain things done before going on 2 weeks holiday. Oh and I asked the same questions of my two co-workers at the local food bank.(NW Wales) both 1st language Welsh speakers One uses both words interchangeably and the other tends to use medru more than gallu but could not define how he distinguishes them. At least this has fixed both words in my mind!
Without seeing the other sentence I cannot comment accurately but if it was something like:
- Dyma beth dw i'n gallu wneud
then that is a shortened version of Dyma beth dw i'n gallu ei wneud - 'This is what I can do.' The ei here is referring back to the beth, and it is usually presumed to be masculine unless specified otherwise somehow.
Thank you for your response. I discovered that, in the other sentence, there was an understood "beth" along with an omitted "ei," which was the cause of the soft mutation of "gwneud." This use of the possessive for direct objects is one of the harder things for me to develop an intuitive grasp of.
I'm not sure where the aspirate or mixed mutation of canu comes from. There's only been a mention of soft mutation so far. Beth is, as far as I know, treated as masculine, whatever it may in fact be referring to. I am hoping things will be clarified when we get onto relative clauses. I think you would need a sentence without the beth, where the ei was referring directly to a feminine noun, to get a different mutation, but I am not sure.
By and large they are equivalent, but they can have slightly different usages, with medru being more of a practical skills thing (playing an instrument, speaking a language, ...) than gallu (being clever at...). medru'r Gymraeg/Saesneg is definitely used in the sense of being able to use or having a good grasp of Welsh/English, say. Not many people would draw a distinction between them in casual usage, though.
Both seem to crop up in the minutes of the Welsh Assembly, anyway.