There are somewhere between 6,000 and 7,000 languages spoken in the world today, and linguists estimate that 50 to 90 percent of them will disappear before the end of this century. Although in some cases this loss is the result of natural disasters, disease, or warfare, it is primarily due to language shift, where one group of people abandons their native tongue in favor of another. This talk will explore the phenomenon of language endangerment and discuss the implications of this loss for societies and for scientific knowledge.