Listen now: Around 7,000 languages are spoken on Earth 1.0. (Photo: Quinn Dombrowski/Flickr) Our latest Freakonomics Radio episode is called “What Would Be the Best Universal Language? (Earth 2.0 Series).” (You can subscribe to the podcast at Apple Podcasts or elsewhere , get the RSS feed , or listen via the media player above.) We explore votes for English, Indonesian, and … Esperanto! The search for a common language goes back millennia, but so much still gets lost in translation.