We have accepted bookings written in German, Japanese, Chinese and English. But we speak English, and Japanese as a rule.
Sometimes a party of guests will have only one person who speaks Japanese or English. Sometimes the person who speaks Japanese is speaking it as a second language.
On one memorable occasion, there were two guests, and one spoke English. But the English conversation was eased by sier to write things in Japanese, and have them interpret it into their native tongue, than to speak English together.