"He is learning Norwegian."
Translation:Han lär sig norska.
This could happen if you just put lär. The word lär doesn't work on its own: it's a transitive verb that requires an object. With sig, it means 'learns', and when the object is someone else, it means 'teaches'.
The word läser however can also mean 'studies', so since the machine tries to correct you to the closest accepted answer, it might show you that.