The ability of native speakers of a language to use words in ways that are socially and culturally appropriate is called

Communicative competence

Explanation:

Communicative competence involves communicating a language by including cultural context. In other words communicating with the right use of words, grammar, phonology and taking into consideration the social knowledge.

It is how a native speaker normally speaks, but for someone who speaks another language it is difficult to be competent.

Hence, the statement here refers to communicative competence.