I get he's excited to find someone that speaks broken Japanese, but did this man just DELIBERATELY get lost after saying he was traumatized last time? I personally think this would have been better if she started speaking English or German or some other language he recognized, but couldn't speak well himself (I would have enjoyed to see him get excited over that only to be back where he started).
Also this is the weirdest slave worker (well beyond the fact that I still don't understand why these fantasy Manga always have slaves. Slavery isn't economically sustainable. I don't see why these world's full of magic bother with something so ineffecient and financially flawed). She has total freedom to leave the store randomly with a customer and can talk back to and refuse customer's whims (or what she taught his whims were). Also she was taught a few Japanese words by her grandmother. This is so far the most interesting character with all the stuff about her I need more information on.