どうして
どうして
adverb
why, how come
1.
why, how come
Used to ask for the reason or cause of something. Slightly more casual than なぜ.
2.
how
Used to ask about the method or way to do something.
どうして is used to ask "why" (reason) or "how" (method).
TWO MEANINGS:
1. Why (reason): どうして来なかったの？ (Why didn't you come?)
2. How (method): どうして行けばいい？ (How should I go?)
FORMALITY COMPARISON:
- どうして: conversational, everyday
- なぜ: formal, written/literary
- なんで: very casual, informal
COMMON PATTERNS:
- どうして〜の？: casual question (with の)
- どうして〜んですか？: polite question
- どうして？！: expressing surprise/disbelief
RESPONSE:
Typically answered with から (because) or ので (since).