The English translation of the manga "Death Note" by Tsugumi Ōba has sold millions of copies around the world — with barely a mention anywhere of the glaring translation error in the title and throughout the work: "Death Note" should in fact be "Death Notebook."

While the Japanese word nōto (ノート) derives from the English word "note," in common use it always means "notebook." Fortunately, "Death Note" makes a catchy title and can be read at a stretch as the "notes" in the "Death Notebook." But this mistake offers a valuable lesson for students of Japanese and translators: Loan words live a life separate from the words that gave birth to them.

Nōto is not unique in this sense. Japan has a long history of commandeering words from other languages and making them its own. Kobo Daishi, one of Japan's first exchange students, allegedly brought back thousands of kanji from China in the eighth century. Words from Portugal and Holland arrived through Nagasaki roughly 1,000 years later. More recently, Japanese has borrowed from English and other languages, and hence there are now legions of words that require thought before you can convert them back into their source language.