Cummins discusses how there are two types of language proficiency - Basic Interpersonal Communicative Skills (BICS) and Cognitive Academic Language Proficiency (CALP). BICS is easier to obtain but CALP takes longer, even for native speakers, to develop. To truly master a language, students need consistent instruction across their entire school day, including in content area classes. Hymes identifies four competencies - grammatical, sociolinguistic, discourse, and strategic - that allow students to adapt language skills for any purpose.