How Efficiency Shapes Human Language

We review recent research on the burgeoning topic of how language structure is shaped by principles of efficiency for communication and learning. Work in this area has infused long-standing ideas in linguistics and psychology with new precision and methodological rigor by bringing together information theory, newly available datasets, controlled experimentation, and computational modeling. We review a number of studies that focus on phenomena ranging from the lexicon through syntactic processes, and which deploy formal tools from information theory and probability theory to understand how and why language works the way that it does. These studies show how a pervasive pressure for efficient usage guides the form of natural language and suggest a rich future for language research in connecting linguistics to cognitive psychology and mathematical theories of communication. Cognitive science applies diverse tools and perspectives to study human language. Recently, an exciting body of work has examined linguistic phenomena through the lens of efficiency in usage: what otherwise puzzling features of language find explanation in formal accounts of how language might be optimized for communication and learning? Here, we review studies that deploy formal tools from probability and information theory to understand how and why language works the way that it does, focusing on phenomena ranging from the lexicon through syntax. These studies show how a pervasive pressure for efficiency guides the forms of natural language and indicate that a rich future for language research lies in connecting linguistics to cognitive psychology and mathematical theories of communication and inference.