Just to make this clear... povi is to be able because you have the ability, scipovi is to be able because you have the knowledge, and rajti is to be able because you have permission?
kapabli = to be able to but not necessarily have the posibility
Mi kapablas ludi pianon sed nun ne povas, ĉar ne estas piano ĉi tie.
Mi scipovas ludi gitaron, sed ne kapablas por manko da instrumento.
Why is "could" not acceptable for "scipovis"?
"Could" should be accepted since it can be used to express ability in the past.
Still feels like the most natural translation of scipovas is can.
"Can" by itself doesn't distinguish between learned ability and capability/permission, the way scipovi and povi do.
Sew she did...