NATO Phonetic Alphabet

The NATO phonetic alphabet is the spelling alphabet used in radiotelephony: every letter has a code word (Alfa, Bravo, Charlie…) that stays recognisable over a noisy line and between people who speak different languages.

Its official name is the ICAO radiotelephony spelling alphabet: it was standardised by the International Civil Aviation Organization and is also used by NATO and the International Telecommunication Union (ITU). That is why it is called the NATO alphabet, ICAO alphabet, aviation alphabet or radio alphabet.

Despite the name, it is not a phonetic alphabet in the linguistic sense: the International Phonetic Alphabet (IPA) transcribes the sounds of languages, while the NATO alphabet exists so that letters are not confused when spoken aloud.

During the Second World War the Allies used English-based spelling alphabets such as the well-known Able, Baker, Charlie. They worked for English speakers but caused problems for everyone else.

After the war ICAO ran a study, with the help of linguist Jean-Paul Vinay of the Université de Montréal, to find words that English, French and Spanish speakers could all pronounce and understand. After a first version in 1951, revised to remove words that were easily confused, the current alphabet has been in force since 1 March 1956 and has not changed since. NATO adopted it in the same period, which gave it its best-known name.

• Alfa is spelled with an f, not Alpha: non-English speakers may not read “ph” as an f.
• Juliett has two ts: a French speaker would treat the final t of “Juliet” as silent.
• Tree instead of three: the “th” sound is hard for many non-native speakers.
• Fife instead of five, so it cannot be mistaken for fire.
• Niner instead of nine, to tell it apart from the German nein (“no”).

• Aviation – pilots and air traffic controllers: the registration G-ABCD is read Golf Alfa Bravo Charlie Delta.
• Drones – for pilots flying near controlled airspace or reading out codes such as their UAS operator number.
• Maritime, military, emergency services and amateur radio – anywhere people talk over the radio.
• Phone and help desk – to dictate emails, booking references, licence plates, serial numbers or passwords without mistakes.

• G-ABCD → Golf Alfa Bravo Charlie Delta
• 121.5 (aviation emergency frequency) → One Two One Decimal Five
• K7X2QP (booking reference) → Kilo Seven X-ray Two Quebec Papa
• AB12 CDE (licence plate) → Alfa Bravo One Two Charlie Delta Echo

For a password, say “capital” or “lower case” before each letter, and ask the listener to read everything back before confirming.

The NATO alphabet is for spelling by voice; Morse code encodes the same letters as short and long signals, sent as sound or light. The two have always lived side by side on the radio: aviation beacons (VOR and NDB) identify themselves in Morse, while talking to the tower is done by voice with the NATO alphabet.

The chart below shows both. To listen to, generate or decode Morse, use the Morse converter with audio and microphone.