This is the 496th most frequent Estonian word.
oska
"Oska" means "to know how" or "to be able to" (when referring to a skill).
'Oskad' asks about someone's skill or ability to play the guitar.
Kas sa oskad mängida kitarri?
Can you play the guitar?
Here 'oskan' indicates the ability to perform the action of singing skillfully.
Ma oskan hästi laulda.
I can sing well.
'Ei oska' specifies the lack of ability or skill in the context of skating at this time.