Peter Ludlow shows how word meanings are much more dynamic than we might have supposed, and explores how meanings are modulated (changed) even during the course of our everyday conversations. When we engage with communicative partners we build micro-languages on the fly—languages that may be fleeting, but which serve our joint interests. Sometimes we sync up on word meanings without reflection, but in many cases we debate the proper modulation of the meanings of our words. Living Words explores the norms that govern the ways in which we litigate word meanings. The resulting view is radical, and Ludlow shows that it has far-reaching consequences for our political and legal discourse and also for some of the deepest and most intractable puzzles that have gripped English-language philosophy for the past 100 years—including puzzles in the foundations of semantics, epistemology, and logic.