Norma × úzus – jazyková příručka jako arbitr

English has no language academy: dictionaries and style guides compete, and nobody can declare a usage officially wrong. Czech has one publicly funded authority, the Ústav pro jazyk český of the Academy of Sciences (ÚJČ), and Czechs take its word seriously, not least because spelling is drilled at school through years of dictations. To argue about Czech like a native you need the three terms Czech linguists use.

Term	What it is	Example
úzus	what people actually say and write	abysme, dvěmi, by jste
norma	what educated speakers accept as standard	můžu beside mohu
kodifikace	the norm written down in reference works	Pravidla českého pravopisu, IJP

The point of the triad is that codification describes the norm and should follow it, with a delay. When usage and codification drift apart, the argument is over whether the codification is lagging (abysme) or the usage is simply wrong (by jste).

The reference works

• Pravidla českého pravopisu, the spelling rules, first issued in 1902; the edition in use today goes back to 1993.
• Slovník spisovné češtiny pro školu a veřejnost (SSČ), and the online Akademický slovník současné češtiny, still being written.
• Internetová jazyková příručka (prirucka.ujc.cas.cz): spelling, inflection and usage notes for most words you will look up. This is the working tool.
• The ÚJČ jazyková poradna, an advice service that answers language questions from the public by phone and email.

How the codification moves

The 1993 Pravidla admitted many doublets in loanwords, filozofie beside filosofie, kurz beside kurs, and set off a long public debate. Colloquial forms such as můžu and děkuju are now standard alongside mohu and děkuji, which sound more formal. Abysme and dvěmi are frequent but not codified. By jste is a different case: it is common, but it breaks the conditional paradigm instead of extending it, and nobody proposes to codify it.

Arguing like a native

Czechs settle disputes by citing the source: Podle Internetové jazykové příručky je tvar dvěmi nespisovný. Learn the labels the reference works use: spisovný (standard), nespisovný (non-standard), hovorový (colloquial but within the standard), knižní (bookish), zastaralý (dated), expresivní (emotionally marked). A C2 speaker checks before correcting anyone and remembers that the codification advises rather than legislates: schools and official documents follow it, and outside them nobody is obliged to.