On the notion 'proper language'

Assuming grammars concern communication, we distinguish (1) a calculus that controls the coding of information and (2) a protocol that controls the transfer of information. Where a calculus abstracts from the objects of communication, a protocol abstracts from the methods of communication. Adhering to a calculus we speak truthfully and adhering to a protocol we speak properly. Given that the notion of 'proper language' applies to writing as well, the minimum variation in method is in constituent-order. Thus, it is the conventions of constituent-order which are constitutive of 'proper language'. Including a description of these allows a grammar to correctly represent a language without being prescriptive.