The Allied military phonetic spelling alphabets prescribed the words that are used to represent each letter of the alphabet, when spelling other words out loud, letter-by-letter, and how the spelling words should be pronounced for use by the Allies of World War II. They are not a "phonetic alphabet" in the sense in which that term is used in phonetics, i.e. they are not a system for transcribing speech sounds.
The Allied militaries – primarily the US and the UK – had their own radiotelephone spelling alphabets which had origins back to World War I and had evolved separately in the different services in the two countries. For communication between the different countries and different services specific alphabets were mandated.
The last WWII spelling alphabet continued to be used through the Korean War, being replaced in 1956 as a result of both countries adopting the ICAO/ITU Radiotelephony Spelling Alphabet, with the NATO members calling their usage the "NATO Phonetic Alphabet".
During WWII, the Allies had defined terminology to describe the scope of communications procedures among different services and nations. A summary of the terms used was published in a post-WWII NATO memo:[1]
Thus, the Combined Communications Board (CCB), created in 1941, derived a spelling alphabet that was mandated for use when any US military branch was communicating with any British military branch; when operating without any British forces, the Joint Army/Navy spelling alphabet was mandated for use whenever the US Army and US Navy were communicating in joint operations; if the US Army was operating on its own, it would use its own spelling alphabet, in which some of the letters were identical to the other spelling alphabets and some completely different.