The aviation phonetic alphabet

Why these words

Why is it Alfa, not Alpha, and Juliett with two Ts?

Because the alphabet was built for people whose first language isn't English. ICAO, the UN body that sets aviation's common standards, keeps the official spelling as Alfa because "alpha" with a ph would not be pronounced correctly by speakers of languages where ph is not read as an f. Juliett carries a second t so that French speakers, who would treat a single final t as silent, say the last syllable out loud. The same thinking shows in the pronunciations: the words were chosen to be live words in English, French and Spanish, easy to say and to recognize over a radio by crews of any nationality, and free of any awkward meaning.

Where did the phonetic alphabet come from?

Spelling alphabets are older than aviation radio. The International Telecommunication Union produced the first internationally recognized one in 1927 and revised it in 1932. In 1941 the United States adopted the "Able Baker" alphabet for its armed forces, and Britain's Royal Air Force took it up two years later. Able Baker was built on English sounds, which was a problem for the rest of the world's aviators.

Between 1948 and 1949, Professor Jean-Paul Vinay of the Université de Montréal worked with ICAO's language section on a replacement, choosing words that existed in English, French and Spanish and that crews could recognize over a noisy radio. The result came into effect for civil aviation on November 1, 1951. After a review led by Britain and the United States that swapped several code words, NATO adopted the alphabet on March 1, 1956, with ICAO's approval and November as the word for N. It has stayed essentially unchanged since, which is why a controller in Tokyo and a pilot from Toledo can spell a call sign to each other without a second thought.

Where will I hear it?

On every radio call that spells something: a private airplane identifies itself by its registration ("Bonanza Six Five Five Golf"), parallel runways are "two seven left" and "two seven right", taxiways carry single letters, and airline flights add "heavy" when they are big jets with strong wakes. If you listen to air traffic control online, the alphabet is the first thing that starts to make sense. Our guide to how air traffic control works explains who is talking to whom, and the glossary covers the rest of the vocabulary.