normative
/ˈnɔ:mətɪv; `nɔrmətɪv/ adj
(fml 文) describing or setting standards or rules of language, behaviour, etc, which should be followed （语言、 行为等）标准的, 规范的
A normative grammar of a language describes how its authors think the language should be spoken or written. 规范语法阐述的是该派语法学家认为的某语言的口语或书面语的标准形式.