BICS (Basic Interpersonal Communicative Skills)
BICS refers to the basic communicative fluency achieved by all normal native speakers of a language. It is cognitively undemanding and contextual and is better understood as the language used by students in informal settings, say, on a playground or cafe. Research by Cummins as well as Virginia Collier suggest that it typically takes language learners 1-3 years to develop BICS if they have sufficient exposure to the second language.
Read more about this topic: Jim Cummins (professor)