This document provides an overview of a lecture on linguistics. It discusses the key properties of human languages, including productivity, creativity, flexibility, compositionality, and the combination of basic units through rules. Productivity refers to the ability of languages to generate an unlimited number of sentences. Most words and sentences are rare based on Zipf's law. Compositionality allows humans to understand novel sentences by recognizing the meanings of parts and how they are combined. The creativity of language use refers to human choices in communication, which remain mysterious.