Requirements

Grammatical side of speech
Demonstrate rather high degree of grammatical control; can use some complex syntactical constructions; do not make mistakes which lead to misunderstanding, and can self-correct most of the mistakes.
Sociolinguistic competence			Can select discourse appropriate to the communicative setting; can explain a problem which has arisen and make it clear that the provider of the service/customer must make a concession; can sustain relationships with native speakers without unintentionally amusing or irritating them or requiring them to behave other than they would with a native speaker.