Researchers had a lucky break that helped them crack the code of Egyptian hieroglyphics, like the ones shown on this artifact. But many lost languages remain undeciphered, with no Rosetta Stone to point the way. (Credit: Zoran Karapancev/shutterstock)

Since the invention of writing several thousands of years ago, humans have come up with myriad scripts that turn the phonetic sounds of spoken languages into something visual. Most of these written languages have already been deciphered, from E