The NATO phonetic alphabet, more accurately known as the International Radiotelephony Spelling Alphabet and also called the ICAO phonetic or ICAO spelling alphabet, as well as the ITU phonetic alphabet, is the most widely used spelling alphabet. Although often called "phonetic alphabets", spelling alphabets are not associated with phonetic transcription systems such as the International Phonetic Alphabet. Instead, the International Civil Aviation Organization (ICAO) alphabet assigned code words acrophonically to the letters of the English alphabet so that critical combinations of letters and numbers can be pronounced and understood by those who transmit and receive voice messages by radio or telephone regardless of language barriers or the presence of transmission static.
The final choice of code words for the letters of the alphabet and for the digits was made after hundreds of thousands of comprehension tests involving 31 nationalities. The qualifying feature was the likelihood of a code word being understood in the context of others. For example, football has a higher chance of being understood than foxtrot in isolation, but foxtrot is superior in extended communication.
