Letter (alphabet) of sounds to make words. A letter is classed as either a consonant or a vowel, depending on how its sound is produced (vowels are "a", "e", "i", "o", "u", and sometimes "y" and "w"). The basic Roman alphabet is used by about one hundred languages, with slight variations. Some versions contain as few as twenty-one characters, some as many as thirty. Letters have specific names associated with them, which may differ with language, dialect, and history. "Z", for example, is usually called "zed" in all English-speaking countries except the US, where it is named "zee". As elements of alphabets,
American Morse code US needing to be proficient in both codes since messages on transatlantic cables were in the international code, and incoming messages needed to be recoded and sent on in American Morse. An attempt in 1854 to make International Morse the standard within the US was rejected by the telegraph companies. Overhead wires, used for most land routes in the US, have nowhere near as big a problem with dispersion as undersea or underground cables and the companies had no wish to retrain their staff. In the late 1890s, radio communication—initially known as "wireless telegraphy"—was invented, and used Morse Code transmissions.