Language Grave (言語墓場, Gengo Hakaba) was an ability that served as a figurative cemetery for Dead Languages. Language Grave was found within Kotonoha Nanase, who served as the repository for all Dead Languages. When a Language becomes a Dead Language, it automatically becomes a part of Kotonoha, providing her instant in-depth knowledge as well as the ability to use the true power of the Language themselves. With Language Grave, Kotonoha was able to recall and recognize any Dead Language she sees, whether through verbal or written means.
When Kotonoha was 8 years old, Language Grave mysteriously awakened.