On iOS you can add new keyboards in Settings/General/Keyboards/Add New Keyboard.

When I learned to type in Russian, I went on Amazon and bought some little keyboard stickers. That helped me learn where the letters were. I also admit to a guilty love of typing Russian and French on my phone, which is (for some reason) much easier. :)

Dancepoints idea is good. I have heard that suggestion for arabic. I haven't really taken the time trying to learn hebrew and knowing some arabic to know how to type. With Hebrew, I am still learning the alphabet in a way because I had a ten year gap in using the language. Arabic, I know the letters and I could probably figure it out with a little memorization (or the stickers like dance point suggests).

But for now I use a shortcut to change the keyboard on screen and type with my mouse. In hebrew it is not like I saying a ton, and more or less with arabic knowing its not efficient.

In addition to what everyone else said, there's usually a stickied post at the top of the Popular section of that forum that has instructions.

The "games" mentioned in this discussion look good, but I haven't tried them.

There are phone apps, downloadable programs and websites that will teach you to type using another alphabet/writing system. You can also just print out a little chart that you make yourself of the keys on the keyboard you'll be typing at, setup a little window on your screen w/ the information, put stickers on your keyboard, buy a new keyboard w/ the keys marked, learn from a book, or take a typing class.

The instructions listed here are pretty good for Windows and Apple systems and may help with the languages that you're interested in.

You don't need to buy different physical computer keyboards to type in those languages. I think a lot of people think this.

For Japanese you don't even need to memorise a new keyboard layout! Japanese people use the same keyboard layout as English. They type on their keyboards in romaji and it automatically converts into hiragana on the screen.

Example: typing these two keys S U converts to す on the screen, and typing these three keys S H I converts to し. That's how Japanese people type the word すし (sushi). ^^

Just need to set the input language to Japanese rather than English, and then it automatically converts romaji to hiragana. :)