§21

Wittgenstein says that the difference between 'five slabs' (report/assertion) and 'five slabs!' (order) does not consist in
(i)...the tone of voice - although the tone of voice may well be generally different in the two cases.
(ii) ...nor does it consist in the grammatical form of the sentence (we could imagine a language in which all assertions had the form and tone of rhetorical questions).

 What is key when distinguishing reports/assertions from orders is the use to which the sentence is put in the language game.

I suppose it is worth noting that although the language (in which all assertions have the form and tone of rhetorical questions) is imagined, rhetorical questions are not. - That is we do, in our own language, have sentences that are in one form (the form of a question), but which play a different role to the role typically played by questions.

What does Wittgenstein have in mind when he is talking about the use of a sentence in the language game?