Translation:The restaurant is next to the department store.
I'm pretty sure it's a cognate of Finnish "koti" and Nortern Sami "goahti".
The words might seem distant, but Hungarian changed a lot of initial occlusives into fricatives (see fi. "kala"/hu. "hal" or fi. "puu"/hu. "fa") and the ending "-ti" in Proto-Uralic seems to often become -z in Hungarian (see fi. "vesi" (the underlying structure is "veti")/hu. "víz"). I'm reasonably sure it's not from German.
(I didn't use asterisks for "-ti" and "veti" because it just makes everything into italics)
I don't know.
It's not something I've ever talked about in English, either, though.
You might ask for the clothes department or the healthcare department, but talking about a "store department" in the abstract doesn't seem like a common thing to me.
Certainly not something I'd expect to learn in a basic course like Duolingo.