NATO phonetic alphabet by those who exchange voice messages by radio or telephone, regardless of language differences or the quality of the communication channel. The 26 code words in the NATO phonetic alphabet are assigned to the 26 letters of the English alphabet in alphabetical order as follows: , Bravo, Charlie, Delta, Echo, Foxtrot, Golf, Hotel, India, , Kilo, Lima, Mike, November, Oscar, Papa, Quebec, Romeo, Sierra, Tango, Uniform, Victor, Whiskey, X-ray, Yankee, Zulu. Strict adherence to the prescribed spelling words is required in order to avoid the problems of confusion that the spelling alphabet is designed to overcome. As noted in a
NATO phonetic alphabet the Federal Aviation Administration (FAA), and the International Amateur Radio Union (IARU), the American Radio Relay League (ARRL), the Association of Public-Safety Communications Officials-International (APCO); and by many military organizations such as the North Atlantic Treaty Organization (NATO) and the now-defunct Southeast Asia Treaty Organization (SEATO). The same alphabetic code words are used by all agencies, but each agency chooses one of two different sets of numeric code words. NATO uses the regular English numeric words (Zero, One, with some alternative pronunciations), whereas the ITU (beginning on April 1, 1969) and the IMO define compound numeric words (Nadazero, Unaone, Bissotwo...).