THE PROBLEM
Bee, tee, vee
Early telephone lines were full of static, so operators began saying a full word for each letter. British military radio operators took up the idea in 1898.
See the historyA HISTORY OF CLEAR SPEECH
M is for Mike,
never for 'em'.
On a crackly line, B, T and V can sound alike.
1956 the alphabet still in use
1956 Year the alphabet took its final form
- A word for every letter
- Tested, not guessed
- Numbers said one by one
- Clear words for noisy lines
A spelling alphabet swaps each letter for a whole word that is hard to mishear. This independent guide explains the one used by pilots, ships, armies and call centres: where it came from, how the words were chosen, and why numbers change too.
THE SHORT ANSWER
One clear word
for each letter.
Letter names are short and easy to confuse.
Whole words carry through the noise.
THE DESIGN
Tested in many voices
The final words were picked after hundreds of thousands of tests with speakers of 31 nationalities, judged on how well each word survived among the others.
How it was chosen
THE NUMBERS
Why 'niner'?
Digits are said one at a time, and some are reshaped: tree, fower, fife and niner, so each one stays distinct on the radio.
Hear a numberHEAR A NUMBER
How does it
sound on air?
Pick a letter or digit to see how the UK aviation manual says to pronounce it. The bar shows how far it moves from everyday English.
Pronunciations from the UK Civil Aviation Authority's Radiotelephony Manual, CAP 413. Reasons from the history of the alphabet.
FOUR WAYS IT IS USED
Not just
for pilots.
The same 26 words turn up far from the cockpit, anywhere a code has to be read out over a phone or radio.
Spell a code letter by letter
Say each letter as its word, so a map grid like DH98 becomes Delta Hotel Niner Eight.
Say digits one by one
On the radio, 17 is read 'one seven' and 60 'six zero'; 'hundred' and 'thousand' are kept for things like altitudes.
Read out long serial numbers
IT staff and airlines use the alphabet for serial numbers and booking records over the phone.
Know the famous pairs
Bravo Zulu means 'well done', and Zulu time means Coordinated Universal Time.
TWO NUMBERS WORTH KNOWING
Built by testing,
then left alone.
One date for when it settled,
one figure for how widely it was tested.
1956
Year the alphabet took its final form
In early 1956 NATO adopted ICAO's refined alphabet, changing one word, Nectar, to November. It has been used without change since.
ADOPTED · 1956
31
Nationalities in the comprehension tests
The final choice followed hundreds of thousands of comprehension tests involving speakers from 31 nationalities.
TESTED · ICAO
Foxtrot beat Football: on its own Football was understood slightly more often, but it was more easily confused with Hotel and Victor, so Foxtrot stayed.
HOW IT WAS CHOSEN
Five rules
for every word.
In 1948-49 ICAO worked with Jean-Paul Vinay, a linguist at the Université de Montréal. Each word had to be a live word in English, French and Spanish, easy for airmen of all languages to say and recognise, and clear over the radio.
It also needed a similar spelling in those languages, to begin with its own letter, and to carry no objectionable meanings. The first result kept 17 of today's words; testing replaced weaker ones, such as Nectar, which was too close to Victor.
Questions
Questions people ask
Is it really called the phonetic alphabet?
That is the common name. Officially it is the International Radiotelephony Spelling Alphabet, and it is not phonetic in the linguist's sense: it gives clearer names for letters rather than a way to write sounds.
Why is it spelled Alfa and Juliett?
Alfa avoids speakers who do not know that 'ph' is said as 'f'; Juliett has two t's so French speakers do not drop a silent final t. The UK CAA's manual prints Alpha but keeps Juliett.
Who designed it?
ICAO led the work with linguist Jean-Paul Vinay of the Université de Montréal from 1948-49, followed by large-scale testing. NATO adopted the refined version in 1956.
Why do pilots say 'niner'?
To keep nine distinct from the German word 'nein'. Three, four and five are also reshaped as tree, fower and fife.
Did anything come before it?
Yes. Early telephone alphabets, British Army and Royal Navy versions in the First World War, and the 'Able Baker' alphabet used by US, British and Australian forces from 1943.
Where the facts come from
Updated