Where Eren moved from a foreign country and barely speaks English, Levi is assigned to help him with his speech because he's the only one who can speak the Eren's language and he slowly starts hoping that Eren doesn't learn English because he's happy being the only one who can talk to him and hear all the pointless and stupid things that Eren's in his mind. When Eren is okay at English Levi hates it when he talks to other people because he doesn't want them to hear his cute accent.