A phonetic alphabet is a list of words used to identify letters in a message transmitted by radio or telephone. Spoken words from an approved list are substituted for letters. For example, the word "Navy" would be "November Alfa Victor Yankee" when spelled in the phonetic alphabet. This practice helps to prevent confusion between similar sounding letters, such as "m" and "n", and to clarify communications that may be garbled during transmission.
An early version of the phonetic alphabet appears in the 1913 edition of The Bluejackets’ Manual. Found in the Signals section, it was paired with the Alphabetical Code Flags defined in the International Code. Both the meanings of the flags (the letter which they represent) and their names (which make up the phonetic alphabet) were selected by international agreement. Later editions included the Morse code signal as well.
Flags with special meanings in Navy signaling were given extra names. These five flags are called governing flags. They convey specific information about how to interpret a signal based on their position among the other flags raised. The governing flags are called Afirm (Affirmative), Int (Interrogatory), Negat (Negative), Option (Optional), Prep (Preparatory). The Navy often substituted these special names for the standard word listed in the phonetic alphabet. During World War II, when it was necessary for the Navy to communicate with the Army or Allied forces, signalmen were directed to use the standard words, given in parentheses.
The words chosen to represent some letters have changed since the phonetic alphabet was introduced. When these changes occur, they are made by international agreement. The current phonetic alphabet was adopted in 1957.