Yes! Despite the title and kanji, the book is written entirely in English. I am half Japanese and so I have an affinity for Japanese language and culture. There are Japanese names—(mostly portmanteaus of various Kanji meaning and sound, but some are more literal. The title has the most significance: Tama (jewel) Ishi (stone) together the mean something akin to "hidden potential" or the concept "diamond in the rough". These are central to the story's theme.