BERKELEY, CALIFORNIA—New computer software is being used to reconstruct protolanguages from modern ones. “It’s very time consuming for humans to look at all the data. There are thousands of languages in the world, with thousands of words each, not to mention all of those languages’ ancestors,” said Dan Klein of the University of California, Berkeley. The software identifies changes in words in a group of languages and then “reverses them” to find early words. “At a much deeper level, our system doesn’t explain why or how certain changes happened, only that they probably did happen,” Klein added.