Japanese

Written Japanese includes three character sets: one stolen from the Chinese (every time we invaded them), one adopted from the set stolen from the Chinese, and one varied from the second set.

There is a keyboard layout, although most (perhaps all) modern systems simply use phonetic input using the standard 101 layout, after which a list of possible strings of characters are displayed based on the phonetic input. Japanese IME, thus, is harder to reproduce than most other languages (I don't know of any other languages with a similar input method), and I've actually yet to see a Linux equivalent of the JP IME on Windows.