どうした？ (doushita?) = What Happened?
なに？ (nani?) = What? 
質問 (shitsumon) = Question.
だれ? (dare) = Who?
いつ? (itsu) = When?

どうして？ (doushite?) = Why?
なぜ? (naze?) = Why?
なんで? (nande?) = Why?

If you want to ask why, you can use naze or doushite or nande.
If you want to ask how, you can use doushite or nande, but cannot use naze. 
Doushite and nande are used not only to ask why but to ask how.

手洗い (tearai) = Bathroom. - when you need to go to do your business
助けて (tasukete) = HELP.
わかりません (wakarimasen) = I don’t understand. 
やめて！ (yamete!) = Stop it!
英語 (eigo) = English
警察 (keisatsu) = Police. - If something really bad happens, these are the guys you’re going to want to ask for.
危ない (abunai) = Dangerous. -  You’ll see this on signs and stuff too. If someone says “abunai” to you, you should probably watch your step.
危険 (kiken) = Peril, Hazard.