Medri is not able rather than able which is says in lesson 1..?

[aran]

But, in English you could ask “can you do it?” and an acceptable answer would be, “I can’t not.”

So, maybe “dwi ddim yn methu” would be an acceptable analogy in Welsh?

In that kind of context, I think you’d be more likely to hear something like ‘Dwi’n methu peidio’…

[stuartfrankel]

Ah, that’s rather more elegant (because of the use of “peidio” in prohibitions). Thanks!