This document discusses language across the curriculum. It outlines that language has many principles and functions, including being arbitrary, vocal, for communication, and unique to a culture. It grows and changes over time. There are eight modes of human activity involving language, such as listening, speaking, reading, and writing. Language is linked to thinking and cognition. There are two types of language proficiency: basic interpersonal communication skills and cognitive academic language proficiency, with the goal being to develop conceptual literacy and solve complex tasks using language.