Morse code is not quite extinct: The U.S. Navy still teaches it to a few sailors, and in 2017, a British man who had broken his leg on a beach used it to signal for help in the dark with a flashlight.

Now Morse code is used largely in airplane navigational systems for identification purposes, says Paul F. Johnston, curator of maritime history at the National Museum of American History.

Morse Code Day is April 27, 2018. Learn how the electric telegraph revolutionized how quickly messages could be received. Katya Vines, PhD You have big news that you want to share with family in ...

However, with Morse code, some things are very short (like an E, for example) and some are much longer (like a zero). In fact, the code tries to reflect the frequency certain letters occur.