Keyboards come in many forms
For example here is Arabic http://www.clavierarabes.com/arabickeyboard/
They come in all languages
Simplified Chinese http://www.linguanaut.com/chinese_keyboard.htm
They come as plug in USB keyboards too , I have USB Arabic keyboard cost abt £25 [$40 US]
same as this http://www.arabic-keyboard.co.uk/
Here are USB Chinese Keyboards 区起企情 恶恶恶大发国进科开噢费门小
http://www.google.co.uk/search?rlz=1C1CHIK_en-gbGB479GB479&sourceid=chrome&ie=UTF-8&q=ARABIC+KEYBOARD#q=chinese+keyboard&hl=en&rlz=1C1CHIK_en-gbGB479GB479&prmd=imvnsa&source=univ&tbm=shop&tbo=u&sa=X&ei=_keuT4mpJ8Ok8QOc1e28DQ&sqi=2&ved=0CJoBEK0E&bav=on.2,or.r_gc.r_pw.r_qf.,cf.osb&fp=b9e7ad663ce380a2&biw=1366&bih=667
You can easily change your Keyboard in the Windows settings and put stickers over the keys, but do not think that pressing any specific letter is the equivalent of that language in English'.
For instance setting your keyboard in windows to be an arabic keyboard does not mean that pressing "A" will give you the arabic equivalent .
I will keep it simple but can go on for ages about this :)