This document discusses the differences between basic interpersonal communication skills (BICS) and cognitive academic language proficiency (CALP) for English language learners. BICS refers to everyday social language skills needed for interactions, while CALP involves more advanced academic language proficiency required for school. The document notes that while BICS develops in 1-2 years, CALP can take 5-7 years and supports are needed to help students develop this. Suggestions are provided for supporting both BICS and CALP development in ELL students.