The (International) Radiotelephony Spelling Alphabet, commonly known as the NATO phonetic alphabet, is the most widely used set of clear code words for communicating the letters of the Roman alphabet, technically a radiotelephonic spelling alphabet. It goes by various names, including NATO spelling alphabet, ICAO phonetic alphabet and ICAO spelling alphabet. The ITU phonetic alphabet and figure code is a rarely used variant that differs in the code words for digits.
To create the code, a series of international agencies assigned 26 code words acrophonically to the letters of the Roman alphabet, so that the names for letters and numbers would be as distinct as possible so as to be easily understood by those who exchanged voice messages by radio or telephone, regardless of language differences or the quality of the connection. The specific code words varied, as some seemingly distinct words were found to be ineffective in real-life conditions. In 1956, NATO modified the then-current set of code words used by the International Civil Aviation Organization (ICAO); this modification then became the international standard when it was accepted by the ICAO that year and by the International Telecommunication Union (ITU) a few years later. The words were chosen to be accessible to speakers of English, French and Spanish.
Although spelling alphabets are commonly called "phonetic alphabets", they should not be confused with phonetic transcription systems such as the International Phonetic Alphabet.
The 26 code words are as follows (ICAO spellings): Alfa, Bravo, Charlie, Delta, Echo, Foxtrot, Golf, Hotel, India, Juliett, Kilo, Lima, Mike, November, Oscar, Papa, Quebec, Romeo, Sierra, Tango, Uniform, Victor, Whiskey, X-ray, Yankee, Zulu. The code words "Alfa" and "Juliett" are spelled that way intentionally to avoid mispronunciations. Numbers are read off as English digits, but the pronunciations of three, four, five, nine and thousand are modified.