It isn't? The Swedish sentence says Hon lyssnar and the English sentence says 'She listens'.
I'm sorry, I had typed an alternate translation and it included på, just got me confused.
Oh right, there's hör på which is a particle verb. That's an accepted answer, and depending on what you input, any accepted answer can get shown to you. hör on its own just means 'hears'. But hör på where på is stressed, means 'listens'.