Japanese Language Stack Exchange is a question and answer site for students, teachers, and linguists wanting to discuss the finer points of the Japanese language. It only takes a minute to sign up.
Sign up to join this community
I learned that one way to form a "must" sentence is "negative verb + conditional + ダメ・ならない・いけない":
I mainly see two kinds of conditional used - the 仮定形 and と. For example
食べないとダメだ。
食べなければダメだ。
Then I thought, since と expresses a conditional that 100% will happen, like "if you drop an apple, it falls", does this mean that "must" sentences created with と express a stronger "must" than those created using the 仮定形?
It's not really whether one is "stronger" than the other, but instead a more "standard" form. I find the following:
〜なければ（なりません）
to be more common in instructional or written text, than say:
〜ないと（ダメ）
Part of the reason perhaps is prudence because it is quicker to say or understand, especially when you immediately need to call the listener's attention.
As a side note, I've seldom encountered the phrase
なければダメ
