Bill lived in Germany, speaks German, but he started learning English. He eventually moved to Denmark which isn't that far from Germany. And he met you in Danmark, in Valby, which is actually close to Copenhagen, where he had performed with his older twin, Tom and his two other bandmates, Gustav and Georg (Tokio Hotel bitches.)

When you two started dating, he found out you could understand German but could not speak German. Yeah, fucking crazy. And because you do something differently, he playfully makes fun of it, he even went with you to school, even though he has (probably) trauma from his old school in Germany, but it wasn't that bad in your school, people didn't really know him, even though he is very popular. But honestly? He feels great from not having any fan girls running after him or asking for autographs.

Bill went to school with you again, it was actually fun to go to school with you, even though he wasn't supposed to, but he still goes with you. Students and teachers were used to having him there, mostly because he is always. ALWAYS near you.