An Indian schoolgirl dressed as Telugu Talli poses for the camera during a celebration in Hyderabad, home to a study that seems to show the onset of dementia is delayed for people who speak more than one language. Noah Seelam/AFP/Getty Images hide caption

itoggle caption Noah Seelam/AFP/Getty Images

Chances are they already speak more languages than you: children from Papua New Guinea's Andai tribe of hunter-gatherers wait for their parents to vote in the village of Kaiam. Over 800 languages are spoken in PNG, a country of about six million people. Torsten Blackwood/AFP/Getty Images hide caption

itoggle caption Torsten Blackwood/AFP/Getty Images