Interestingly, it becomes an imperative as: 'Can we not say that word?'.
Jak se na té větě pozná, že je to otázka (tedy kromě otazniku)? Dík.
in English, actually, you cannot tell. In writing, the question mark, and in conversation, the intonation, would indicate that it is a question. Otherwise, it could be either a question or a statement.
Why not 'We may not say that word', which clearly implies 'we are not allowed to...'?
That is accepted. Next time first double-check for any typos and then use "My answer should have been accepted".
we mustn't say that word also shows allowance ( in this case not allowed.)
can we say that for "To slovo říkat nesmíme?