This document discusses two major approaches to language universals proposed by Noam Chomsky and Joseph Greenberg. Chomsky's approach claims that language universals are innate properties of human language that allow humans to acquire language. Greenberg examined 30 languages and found general principles that govern all human languages, like morphologic and syntactic patterns. The two approaches differ in their data sources - Chomsky focuses on one language's abstract structures while Greenberg compares surface structures across many languages. They also propose different explanations for why language universals exist, like innate properties versus reflecting human cognition and social interaction.