How do you write Japanese Characters on an English keyboard? (for submitting dictation, also writing samples)
The process is slightly different depending on your operating system, but here are some helpful links:
http://www.yesjapan.com/install_japanese/ - for Windows Vista/7/8
http://www.yesjapan.com/install_japanese/windows_xp/ - for Windows XP
http://www.yesjapan.com/install_japanese/mac_osx - for OSX
If you’re on Linux, the process depends on your desktop environment.
Once the keyboard is installed, you should be able to just enable the keyboard and then start typing as you would normally. Then when you hit space at the end of a word/sentence the input method will offer you transcriptions, e.g. if you type ohayou you’ll be offered おはよう、 お早う and オハヨウ
Here is another helpful link:
Good luck!
Thanks for adding that about Linux, Imyirtseshem, I’m using Ubuntu myself but was unsure about how this would change between distros/DEs.