View full lesson: http://ed.ted.com/lessons/how-languages-evolve-alex-gendler

Over the course of human history, thousands of languages have developed from what was once a much smaller number. How did we end up with so many? And how do we keep track of them all? Alex Gendler explains how linguists group languages into language families, demonstrating how these linguistic trees give us crucial insights into the past.

Lesson by Alex Gendler, animation by Igor Coric.