Japanese

Forms

• Dictionary

  Base form, listed in dictionaries. Plain affirmative present.

• Polite 〜ます

  Neutral-polite present. The 〜ます stem feeds many other forms.

• Negative 〜ない

  Plain "doesn't / won't". Conjugates like an い-adjective.

• Negative polite 〜ません

  Polite negative.

• Past 〜た

  Plain past. Same stem rules as the て-form.

• Past polite 〜ました

  Polite past.

• Past negative 〜なかった

  Plain "didn't". 〜ませんでした for polite.

• て-form

  Connective: requests, linking clauses, continuous (〜ている). The key form.

Full conjugation overview on Wikipedia.