NATO Phonetic Alphabet

What the NATO phonetic alphabet is

The NATO phonetic alphabet, formally the International Radiotelephony Spelling Alphabet, assigns a code word to each of the 26 letters so that spelling can be understood over a bad connection or in a noisy room. "B", "D", "P", "T" and "V" all sound alike on a crackly radio; "Bravo", "Delta", "Papa", "Tango" and "Victor" do not. The words were chosen to be recognizable to speakers of English, French and Spanish, to be easy to pronounce, and to be distinct from one another even when half the syllables are lost.

Despite the name, it is not a phonetic transcription system like the IPA used in dictionaries; it is a spelling alphabet. The "phonetic" refers to spelling by sound.

History: from Able Baker to Alfa Bravo (1956)

Spelling alphabets go back to the early days of telephony and radio, and every service had its own. During the Second World War the US and UK militaries used the "Able Baker" alphabet (Able, Baker, Charlie, Dog, Easy, Fox…), but it was built around English sounds and did not work well for allies who spoke other languages.

After the war the International Civil Aviation Organization (ICAO) commissioned research into words that would be intelligible across languages, tested them with pilots and controllers, and after several revisions adopted the alphabet we use today, which came into force on 1 March 1956. NATO adopted it the same year, which is why it carries the NATO name, and the International Telecommunication Union later wrote it into its radio regulations. Apart from the spellings "Alfa" and "Juliett", it has not changed since.

Where it is used

• Aviation. Every airline flight, aircraft registration, taxiway and clearance is spelled this way between pilots and air traffic control, worldwide.
• Military and emergency services. Call signs, grid references and unit names; police forces in some countries use their own variants.
• Maritime radio. Vessel names and call signs over VHF, where it lives alongside Morse-era conventions such as Mayday and Pan-Pan.
• Amateur radio. Operators spell their call signs ("kilo-six-alfa-bravo-charlie") on every contact, and the same letters are sent in Morse on CW.
• Phone support and everyday life. Reading out a booking reference, an email address or a license plate: "M as in Mike, S as in Sierra". Use the "A as in Alfa" format in the tool above for this.

How to spell with it

Say the code word for each letter, pause briefly between words, and speak digits one at a time. For a mixed string like a postcode or flight number, run through it in order without grouping: "SW1A 2AA" becomes "Sierra Whiskey Wun Alfa, Too Alfa Alfa". If the listener is not familiar with the alphabet, the "A as in Alfa" form is friendlier. When accuracy really matters (radio), have the listener read the string back.

Phonetic alphabet and Morse code

The two systems solve the same problem in different media. Morse code makes letters distinct in a signal that can only be on or off; the phonetic alphabet makes them distinct in a voice channel. Radio operators learn both, and the chart above pairs them so you can see, for example, that "Sierra" is ... and "Oscar" is ---, which together spell the famous SOS. For the full dots-and-dashes reference, see the Morse code alphabet.