standard; norm; criterion · (adjective) standard · good; correct; conforming to a standard

There are many people in the world studying English, so English people are used to learners' non-standard accents, their grammatical errors and so on.

Standard Chinese, commonly referred to as Mandarin, is based on Pekinese.

You have to learn standard English.

We tried to come up to the standard.

The criterion of the scientific status of a theory is its falsifiability, or refutability, or testability.