Spelling Alphabets - Voice Procedure

Voice Procedure

Spelling alphabets are especially useful when speaking in a noisy environment when clarity and promptness of communication is essential, for example during two-way radio communication between an aircraft pilot and air traffic control, or in military operations. Whereas the names of many letters sound alike, the set of replacement words can be selected to be as distinct from each other as possible, to minimise the likelihood of ambiguity or mistaking one letter for another. For example, if a burst of static cuts off the start of an English-language utterance of the letter J, it may be mistaken for A or K. In the international radiotelephony spelling alphabet known as the ICAO (or NATO) phonetic alphabet, the sequence J-A-K would be pronounced Juliet-Alpha-Kilo. Some voice procedure standards require numbers to be spelled out digit by digit, so some spelling alphabets replace confusable digit names with more distinct alternatives; for example, the NATO alphabet has "niner" for 9 to distinguish it better from 5 and the German word "nein".