Over the centuries, many words from foreign languages were incorporated into the Japanese language, especially from the Chinese and English languages.

A large amount of Chinese words were introduced together with the Chinese writing system in the 5th century and for many centuries afterwards. Chinese loan words are naturally written in kanji (Chinese characters).

In more recent times, many words were also borrowed from Portuguese, Dutch, German (especially from the fields of medicine and mountaineering), French and Italian (especially from the fields of music and food), and, of course, English which is the origin of most modern loan words. Non-Chinese loan words are written in katakana.

Loan words are often heavily Japanized in various ways, which is a complicating factor not only for students of the Japanese language but also for Japanese students of foreign languages:

  • The pronunciation of loan words is Japanized, and sometimes quite different from the original pronunciation: e.g. curtain=kāten, elevator=elebētā, girl=gāru.
  • Many loan words get abbreviated in ways they do not get abbreviated in the original language: e.g. sūpaa=supermarket, kilo=kilometer (and kilogram), depāto=department store, wāpuro=word processor.
  • The meanings of some loan words do not correspond with the words' original meanings: e.g. "manshon" from the English "mansion" means "apartment".
  • And finally, some "loan words" are actually Japanese creations rather than loan words. For example, "salaryman" is a Japanese word for a typical Japanese company worker, while the "walkman" even found its way back into English dictionaries.