This document discusses the relationship between language, speech, and thought. It makes three key points: 1. Language is a human's primary means of communication that is learned and transmitted through social interaction. It involves the creation and use of symbolic systems. 2. Speech is the vocalization of language and is how humans recognize and understand spoken words. It is discovered through both speech production and perception. 3. Thought is strongly connected to language and influences how humans organize and communicate ideas. The Sapir-Whorf hypothesis proposes that language determines the categories and content of thought. The relationship between thought and speech evolves over time.