Morse code is learned by memorizing the unique dot and dash patterns that make up the language, and then practicing spelling out longer words and phrases to achieve comprehension. Morse code is a method of transmitting textual information in a sequence of dots and dashes, which correspond to letters of the alphabet, numerals and punctuation.
Morse code was originally developed as the language system for the telegraph in the 1890s and for the radio in the modern era, before the advent of voice transmission. Morse code was an essential tool during World War II for communication between warplanes, warships and naval bases. In 1999, the world's maritime nations implemented the Global Maritime Distress Safety System, an international radio safety system that replaced Morse code. The U.S. Navy and Coast Guard no longer monitor the Morse code radio frequencies.
Today, satellites and high-frequency radios have replaced many previous uses of Morse code for communication. Still, pilots and air traffic controllers use Morse code on occasion, and Boy Scouts can receive a merit badge for demonstrating knowledge of Morse code. Morse code can communicate the distress message "SOS" by reflecting sunlight off a mirror or switching a flashlight in the appropriate rhythm.