"Mae hi'n bum munud ar hugain."

Translation: It is twenty-five minutes.

[Wynnigheard]

This sentence makes very little sense out of context.

[StephenDunscombe]

Does "ar" add h- to vowel-initial words?

[Jonlang_]

Only when they're feminine I think (as indicated by mae hi'n as opposed to mae e'n.