ICAO Phonetic Alphabet
The phonetic alphabet eliminates the ambiguity of letters that sound similar over radio — B and D, M and N, S and F — by replacing each letter with a distinct, internationally recognisable word. It is mandatory in all ICAO-standardised aviation communications.
The 26 Code Words
A
Alpha
AL-fah
Derived from the Greek letter Alpha. Spelling changed from "Alfa" in earlier drafts to ensure non-English speakers pronounced it with two clear syllables.
B
Bravo
BRAH-voh
Italian and Spanish for "well done." Selected for its clear two-syllable distinctiveness and universal recognisability across European languages.
C
Charlie
CHAR-lee
A common English given name. Chosen for its strong initial consonant and clear differentiation from similar-sounding letters like D, E and G.
D
Delta
DELL-tah
The Greek letter Delta (Δ). Also the name of the Nile delta, making it familiar across many cultures. No confusion with the word "delta" in most languages.
E
Echo
EH-koh
The acoustic phenomenon of reflected sound. Short, distinctive and unambiguous in virtually all languages tested during ICAO selection.
F
Foxtrot
FOKS-trot
A ballroom dance. Replaced the earlier "Fox" to add a second syllable, improving distinctiveness over radio. The two-word compound made it unmistakable.
G
Golf
GOLF
The sport. Selected for its clear single syllable and strong initial consonant. Internationally recognised due to the global spread of the sport.
H
Hotel
HOH-tell
Universally understood across languages due to widespread use in travel and commerce. Clear differentiation from other H-starting alternatives.
I
India
IN-dee-ah
The country. Selected because "India" is recognisable in most world languages and has a strong three-syllable structure with no ambiguous consonants.
J
Juliett
JEW-lee-ett
Shakespeare's Juliet. Spelled with a double-t in ICAO documentation to ensure non-English speakers stress the second syllable (Ju-LIETT). Earlier draft used "Julie."
K
Kilo
KEY-loh
The metric prefix for 1,000, universally known through the metric system. Also used as a unit prefix in aviation (kilograms, kilofeet).
L
Lima
LEE-mah
The capital of Peru. Selected because "Lima" is clearly two syllables with no ambiguous sounds. Chosen over other L-words that were too similar to existing code words.
M
Mike
MIKE
A common English given name. Short, punchy and completely unambiguous. Also the informal term for a microphone, making it familiar in communications contexts.
N
November
no-VEM-ber
The month. A long, distinctive word with no sound similarity to any other code word. The five syllables make accidental confusion virtually impossible.
O
Oscar
OSS-car
A common given name and the name of the Academy Award statuette. Replaced "Option" in earlier drafts. Strong first syllable, no ambiguity.
P
Papa
PAH-pah
The informal word for father in many languages. Universally understood, strongly two-syllable, and clearly distinct from Q and other P-alternatives.
Q
Quebec
keh-BECK
The Canadian province. Selected for its unique QU opening — no other code word begins with this combination. Also anchors the important Q-code system in aviation.
R
Romeo
ROH-me-oh
Shakespeare's Romeo. Three distinctive syllables with no sound similarity to other code words. Internationally recognisable across cultures.
S
Sierra
see-AIR-ah
A Spanish word for a mountain range with jagged peaks. Three syllables, the double-r sound is distinctive, and it is familiar from geography across many languages.
T
Tango
TANG-go
The Argentine dance. Two clear syllables, strong consonants, internationally known. Replaced earlier alternatives that were less distinctive on radio.
U
Uniform
YOU-nee-form
The word for a standardised outfit. Three syllables, completely unambiguous, and universally understood due to its use in military and school contexts worldwide.
V
Victor
VIK-tor
A common given name meaning "winner." Two clear syllables, strong V opening, no confusion with other code words. Replaced earlier draft "Vice."
W
Whiskey
WISS-key
The spirit distilled from grain. Two syllables with a distinctive WH opening. Internationally known and completely unambiguous on radio.
X
X-ray
EKS-ray
The electromagnetic radiation used in medical imaging. The only two-word code, but selected because no single X-word was sufficiently distinctive across all tested languages.
Y
Yankee
YANG-kee
An informal term for an American, widely understood internationally. Two syllables, strong Y opening, no risk of confusion with other code words.
Z
Zulu
ZOO-loo
The South African ethnic group and language. Two syllables, completely distinctive, and chosen for its strong Z opening. Also adopted as the suffix for UTC time in aviation (e.g. 1400Z).
History
The need for a standardised phonetic alphabet grew with military and civil aviation in the early 20th century. Several competing systems existed: the RAF used Able Baker Charlie in WWII; the US military used a similar system. Conflicts arose when multinational crews used different systems on the same frequency.
ICAO commissioned a scientific study in the early 1950s testing word intelligibility across different languages and radio conditions. The current alphabet was adopted in 1956, with each word selected for maximum distinctiveness across the languages spoken by the majority of international aviation personnel.
Digits
Along with the alphabet, ICAO standardises digit pronunciation to prevent confusion: Zero, One, Two, Tree (not Three), Fower (not Four), Fife (not Five), Six, Seven, Ait (not Eight), Niner (not Nine). The altered pronunciations prevent confusion between similar-sounding numbers across languages.