The Swedish grammatical tradition has its roots in language cultivation and standardisation. The normative ambition became less marked in the 19th century; and in the 20th century grammar became a regular academic discipline; with descriptive and explanatory aims. The grammar of the Swedish Academy was conceived from the start as a descriptive reference grammar of contemporary standard language. It is obvious; though; that such a descriptive grammar can also be read as a normative text; since it presupposes the existence of a standard language; distinguished from non-standard language variants: dialects; obsolete language; child language etc. It is demonstrated how the boundaries of standard language are not so easy to define. It is also reasonable to assume that the reference grammar can be used as an instrument in language cultivation; since the actual rules of the standard language exposed by the grammar can be taken over or modified as a standard which is explicitly recommended. Some problems connected with normative rules of thumb are illustrated against the background of the real patterns of standard language use.