| Alfa | November | |
| Bravo | Oscar | |
| Charlie | Papa | |
| Delta | Quebec | |
| Echo | Romeo | |
| Foxtrot | Sierra | |
| Golf | Tango | |
| Hotel | Uniform | |
| India | Victor | |
| Juliett | Whiskey | |
| Kilo | Xray | |
| Lima | Yankee | |
| Mike | Zulu | |
Although spelling alphabets are commonly called "phonetic alphabets", they are not phonetic in the sense of phonetic transcription systems such as the International Phonetic Alphabet.
To create the code, a series of international agencies assigned 26 clear-code words (also known as "phonetic words") acrophonically to the letters of the Roman alphabet, with the goal that the letters and numbers would be easily distinguishable from one another over radio and telephone. The words were chosen to be accessible to speakers of English, French and Spanish. Some of the code words were changed over time, as they were found to be ineffective in real-life conditions. In 1956, NATO modified the then-current set used by the International Civil Aviation Organization (ICAO); this modification then became the international standard when it was accepted by ICAO that year and by the International Telecommunication Union (ITU) a few years later.[1]
The 26 code words are as follows (ICAO spellings): , Bravo, Charlie, Delta, Echo, Foxtrot, Golf, Hotel, India, , Kilo, Lima, Mike, November, Oscar, Papa, Quebec, Romeo, Sierra, Tango, Uniform, Victor, Whiskey, X-ray, Yankee, Zulu.[2] (Alfa) and (Juliett) are spelled that way to avoid mispronunciation by people unfamiliar with English orthography; NATO changed (X-ray) to (Xray) for the same reason.[3] The code words for digits are their English names, though with their pronunciations modified in the cases of three, four, five, nine and thousand.[4]
The code words have been stable since 1956. A 1955 NATO memo stated that:
Soon after the code words were developed by ICAO (see history below), they were adopted by other national and international organizations, including the ITU, the International Maritime Organization (IMO), the United States Federal Government as Federal Standard 1037C: Glossary of Telecommunications Terms[5] and its successors ANSI T1.523-2001[6] and ATIS Telecom Glossary (ATIS-0100523.2019)[7] (all three using the spellings "Alpha" and "Juliet"), the United States Department of Defense,[8] the Federal Aviation Administration (FAA) (using the spelling "Xray"), the International Amateur Radio Union (IARU), the American Radio Relay League (ARRL), the Association of Public-Safety Communications Officials-International (APCO), and by many military organizations such as NATO (using the spelling "Xray") and the now-defunct Southeast Asia Treaty Organization (SEATO).
The same alphabetic code words are used by all agencies, but each agency chooses one of two different sets of numeric code words. NATO uses the regular English numerals (zero, one, two etc., though with some differences in pronunciation), whereas the ITU (beginning on 1 April 1969) and the IMO created compound code words (nadazero, unaone, bissotwo etc.). In practice the compound words are used very rarely.
A spelling alphabet is used to disambiguate those parts of a message that contain letters and digits, because the names of many letters sound similar, for instance bee and pee, en and em or ef and ess. The potential for confusion increases if static or other interference is present, as is commonly the case with radio and telephonic communication. For instance, the target message "proceed to map grid DH98" would be transmitted as proceed to map grid Delta-Hotel-Niner-Ait.
Civilian industry uses the code words to avoid similar problems in the transmission of messages by telephone systems. For example, it is often used in the retail industry where customer or site details are conveyed by telephone (for example to authorize a credit agreement or confirm stock codes), although ad-hoc code words are often used in that instance. It has been used by information technology workers to communicate serial numbers and reference codes, which are often very long, by voice. Most major airlines use the alphabet to communicate passenger name records (PNRs) internally, and in some cases, with customers. It is often used in a medical context as well.
Several codes words and sequences of code words have become well-known, such as Bravo Zulu (letter code BZ) for "well done",[9] Checkpoint Charlie (Checkpoint C) in Berlin, and Zulu Time for Greenwich Mean Time or Coordinated Universal Time. During the Vietnam War, the US government referred to the Viet Cong guerrillas and the group itself as VC, or Victor Charlie; the name "Charlie" became synonymous with this force.
pronounced as /notice/
The final choice of code words for the letters of the alphabet and for the digits was made after hundreds of thousands of comprehension tests involving 31 nationalities. The qualifying feature was the likelihood of a code word being understood in the context of others. For example, Football has a higher chance of being understood than Foxtrot in isolation, but Foxtrot is superior in extended communication.
Pronunciations were set out by the ICAO before 1956 with advice from the governments of both the United States and United Kingdom.[10] To eliminate national variations in pronunciation, posters illustrating the pronunciation desired by ICAO are available. However, there remain differences in the pronunciations published by ICAO and other agencies, and ICAO has apparently conflicting Latin-alphabet and IPA transcriptions. At least some of these differences appear to be typographic errors. In 2022 the Deutsches Institut für Normung (DIN) attempted to resolve these conflicts.
Just as words are spelled out as individual letters, numbers are spelled out as individual digits. That is, 17 is rendered one seven and 60 as six zero. Depending on context, the word thousand may be used as in English, and for whole hundreds only (when the sequence 00 occurs at the end of a number), the word hundred may be used. For example, 1300 is read as one three zero zero if it is a transponder code or serial number, and as one thousand three hundred if it is an altitude or distance.
The ICAO, NATO, and FAA use modifications of English digits as code words, with 3, 4, 5 and 9 being pronounced tree, fower (rhymes with lower), fife and niner. The digit 3 is specified as tree so that it will not be mispronounced sri (and similarly for thousand); the long pronunciation of 4 (still found in some English dialects) keeps it somewhat distinct from for; 5 is pronounced with a second "f" because the normal pronunciation with a "v" is easily confused with "fire" (a command to shoot); and 9 has an extra syllable to keep it distinct from the German word nein "no". (Prior to 1956, three and five had been pronounced with the English consonants, but as two syllables.) For direction presented as the hour-hand position on a clock, "ten", "eleven" and "twelve" may be used with the word "o'clock".
The ITU and IMO, however, specify a different set of code words. These are compounds of the ICAO words with a Latinesque prefix.[11] The IMO's GMDSS procedures permits the use of either set of code words.[11]
There are two IPA transcriptions of the letter names, from the International Civil Aviation Organization (ICAO) and the Deutsches Institut für Normung (DIN). Both authorities indicate that a non-rhotic pronunciation is standard.[12] That of the ICAO, first published in 1950 and reprinted many times without correction (vd. the error in 'golf'), uses a large number of vowels. For instance, it has six low/central vowels: pronounced as /link/ pronounced as /link/ pronounced as /link/ pronounced as /link/ pronounced as /link/ pronounced as /link/. The DIN consolidated all six into the single low-central vowel pronounced as /[a]/. The DIN vowels are partly predictable, with pronounced as /[{{IPAlink|ɪ}} {{IPAlink|ɛ}} {{IPAlink|ɔ}}]/ in closed syllables and pronounced as /[{{IPAlink|i}} {{IPAlink|e}}/[[diphthong|ei̯]] pronounced as /ink/]/ in open syllables apart from echo and sierra, which have pronounced as /[ɛ]/ as in English, German and Italian. The DIN also reduced the number of stressed syllables in bravo and x-ray, consistent with the ICAO English respellings of those words and with the NATO change of spelling of x-ray to xray so that people would know to pronounce it as a single word.
| Symbol | Code word | DIN 5009 (2022) [13] | (1950)[14] | ||
|---|---|---|---|---|---|
| English respelling | |||||
| A | Alfa | pronounced as /ˈalfa/ | pronounced as /ˈælfa/ | AL fah | |
| B | Bravo | pronounced as /ˈbravo/ | pronounced as /ˈbraːˈvo/ | BRAH voh | |
| C | Charlie | pronounced as /ˈtʃali/ (or pronounced as /ˈʃali/) | pronounced as /ˈtʃɑːli/ (or pronounced as /ˈʃɑːli/) | CHAR lee (or SHAR lee)[15] | |
| D | Delta | pronounced as /ˈdɛlta/ | pronounced as /ˈdeltɑ/ | DELL tah | |
| E | Echo | pronounced as /ˈɛko/ | pronounced as /ˈeko/ | ECK oh | |
| F | Foxtrot | pronounced as /ˈfɔkstrɔt/ | pronounced as /ˈfɔkstrɔt/ | FOKS trot | |
| G | Golf | pronounced as /ˈɡɔlf/ | pronounced as /ɡʌlf/ | golf | |
| H | Hotel | pronounced as /hoˈtɛl/ | pronounced as /hoːˈtel/ | ho TELL | |
| I | India | pronounced as /ˈɪndia/ | pronounced as /ˈindi.ɑ/ | IN dee ah | |
| J | Juliett | pronounced as /ˈdʒuliˈɛt/ | pronounced as /ˈdʒuːli.ˈet/ | JEW lee ETT | |
| K | Kilo | pronounced as /ˈkilo/ | pronounced as /ˈkiːlo/ | KEY loh | |
| L | Lima | pronounced as /ˈlima/ | pronounced as /ˈliːmɑ/ | LEE mah | |
| M | Mike | pronounced as /ˈmai̯k/ | pronounced as /mɑik/ | mike | |
| N | November | pronounced as /noˈvɛmba/ | pronounced as /noˈvembə/ | no VEM ber | |
| O | Oscar | pronounced as /ˈɔska/ | pronounced as /ˈɔskɑ/ | OSS cah | |
| P | Papa | pronounced as /paˈpa/ | pronounced as /pəˈpɑ/ | pah PAH | |
| Q | Quebec | pronounced as /keˈbɛk/ | pronounced as /keˈbek/ | keh BECK | |
| R | Romeo | pronounced as /ˈromio/ | pronounced as /ˈroːmi.o/ | ROW me oh | |
| S | Sierra | pronounced as /siˈɛra/ | pronounced as /siˈerɑ/ | see AIR rah | |
| T | Tango | pronounced as /ˈtaŋɡo/ | pronounced as /ˈtænɡo/ | TANG go | |
| U | Uniform | pronounced as /ˈjunifɔm/ (or pronounced as /ˈunifɔm/) | pronounced as /ˈjuːnifɔːm/ (or pronounced as /ˈuːnifɔrm/) | (or) | |
| V | Victor | pronounced as /ˈvɪkta/ | pronounced as /ˈviktɑ/ | VIK tah | |
| W | Whiskey | pronounced as /ˈwɪski/ | pronounced as /ˈwiski/ | WISS key | |
| X | Xray, x-ray | pronounced as /ˈɛksrei̯/ | pronounced as /ˈeksˈrei/ | ECKS ray | |
| Y | Yankee | pronounced as /ˈjaŋki/ | pronounced as /ˈjænki/ | YANG key | |
| Z | Zulu | pronounced as /ˈzulu/ | pronounced as /ˈzuːluː/ | ZOO loo | |
There is no authoritative IPA transcription of the digits. However, there are respellings into both English and French, which can be compared to clarify some of the ambiguities and inconsistencies.
| Symbol | Code word | Respellings | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
(English) | [16] (French) | CCEB 2016[17] | [18] | (English)[19] | (French) | 1957[20] | [21] | |||
| 1 | One, unaone | WUN | OUANN | wun | wun | OO-NAH-WUN | OUNA-OUANN | wun | wun, [22] | |
| 2 | Two, bissotwo | TOO | TOU | too | too | BEES-SOH-TOO | BIS-SO-TOU | too | too | |
| 3 | Three, terrathree | TREE | TRI | tree | tree | TAY-RAH-TREE | TÉ-RA-TRI | thuh-ree | tree | |
| 4 | Four, kartefour | FOW-er | FO eur | FOW-er | fow-er | KAR-TAY-FOWER | fo-wer | fow-er | ||
| 5 | Five, pantafive | FIFE | FA ÏF | fife | fife | PAN-TAH-FIVE | PANN-TA-FAIF | fi-yiv | fife | |
| 6 | Six, soxisix | SIX | SIKS | six | six | SOK-SEE-SIX | SO-XI-SICKS | six | six | |
| 7 | Seven, setteseven | SEV-en | SÈV n | SEV-en | sev-en | SAY-TAY-SEVEN | SÉT-TÉ-SEV'N | seven | sev-en | |
| 8 | Eight, oktoeight | AIT | EÏT | ait | ait | OK-TOH-AIT | OK-TO-EIT | ate | ait | |
| 9 | Nine, novenine[23] | NIN-er | NAÏ neu | NINE-er | nin-er | NO-VAY-NINER | niner | nin-er | ||
| 0 | Zero, nadazero | ZE-RO[24] | ZI RO | ZE-ro | ze-ro / zee-ro | [25] [26] | zero | ze-ro | ||
| 00 | Hundred | HUN-dred | HUN-dred | (zero zero) | (hundred) | hun-dred | ||||
| 000 | Thousand | (zero zero zero) | (thousand) | tou-sand | ||||||
| (decimal point) | Decimal, (FAA) point | DÈ SI MAL | (decimal) | (point) | DAY-SEE-MAL | DÉ-SI-MAL | ||||
CCEB has code words for punctuation, including those in the table below.
| Symbol | Code word | |
|---|---|---|
| . | stop (when not a decimal point) | |
| , | comma (when not a decimal comma) | |
| - | hyphen (FAA "dash") | |
| / | slant | |
| ( | brackets on | |
| ) | brackets off |
Others are: "colon", "semi-colon", "exclamation mark", "question mark", "apostrophe", "quote", and "unquote".[17]
Prior to World War I and the development and widespread adoption of two-way radio that supported voice, telephone spelling alphabets were developed to improve communication on low-quality and long-distance telephone circuits.
The first non-military internationally recognized spelling alphabet was adopted by the CCIR (predecessor of the ITU) during 1927. The experience gained with that alphabet resulted in several changes being made during 1932 by the ITU. The resulting alphabet was adopted by the International Commission for Air Navigation, the predecessor of the ICAO, and was used for civil aviation until World War II. It continued to be used by the IMO until 1965.
Throughout World War II, many nations used their own versions of a spelling alphabet. The US adopted the Joint Army/Navy radiotelephony alphabet during 1941 to standardize systems among all branches of its armed forces. The US alphabet became known as Able Baker after the words for A and B. The Royal Air Force adopted one similar to the United States one during World War II as well. Other British forces adopted the RAF radio alphabet, which is similar to the phonetic alphabet used by the Royal Navy during World War I. At least two of the terms are sometimes still used by UK civilians to spell words over the phone, namely F for Freddie and S for Sugar.
To enable the US, UK, and Australian armed forces to communicate during joint operations, in 1943 the CCB (Combined Communications Board; the combination of US and UK upper military commands) modified the US military's Joint Army/Navy alphabet for use by all three nations, with the result being called the US-UK spelling alphabet. It was defined in one or more of CCBP-1: Combined Amphibious Communications Instructions, CCBP3: Combined Radiotelephone (R/T) Procedure, and CCBP-7: Combined Communication Instructions. The CCB alphabet itself was based on the US Joint Army/Navy spelling alphabet. The CCBP (Combined Communications Board Publications) documents contain material formerly published in US Army Field Manuals in the 24-series. Several of these documents had revisions, and were renamed. For instance, CCBP3-2 was the second edition of CCBP3.
During World War II, the US military conducted significant research into spelling alphabets. Major F. D. Handy, directorate of Communications in the Army Air Force (and a member of the working committee of the Combined Communications Board), enlisted the help of Harvard University's Psycho-Acoustic Laboratory, asking them to determine the most successful word for each letter when using "military interphones in the intense noise encountered in modern warfare.". He included lists from the US, Royal Air Force, Royal Navy, British Army, AT&T, Western Union, RCA Communications, and that of the International Telecommunications Convention. According to a report on the subject:
After World War II, with many aircraft and ground personnel from the allied armed forces, "Able Baker" was officially adopted for use in international aviation. During the 1946 Second Session of the ICAO Communications Division, the organization adopted the so-called "Able Baker" alphabet[27] that was the 1943 US–UK spelling alphabet. However, many sounds were unique to English, so an alternative "Ana Brazil" alphabet was used in Latin America. In spite of this, International Air Transport Association (IATA), recognizing the need for a single universal alphabet, presented a draft alphabet to the ICAO during 1947 that had sounds common to English, French, Spanish and Portuguese.
From 1948 to 1949, Jean-Paul Vinay, a professor of linguistics at the Université de Montréal worked closely with the ICAO to research and develop a new spelling alphabet.[28] [27] The directions of ICAO were that "To be considered, a word must:
After further study and modification by each approving body, the revised alphabet was adopted on, to become effective on 1 April 1952 for civil aviation (but it may not have been adopted by any military).
Problems were soon found with this list. Some users believed that they were so severe that they reverted to the old "Able Baker" alphabet. Confusion among words like Delta and Extra, and between Nectar and Victor, or the poor intelligibility of other words during poor receiving conditions were the main problems. Later in 1952, ICAO decided to revisit the alphabet and their research. To identify the deficiencies of the new alphabet, testing was conducted among speakers from 31 nations, principally by the governments of the United Kingdom and the United States. In the United States, the research was conducted by the USAF-directed Operational Applications Laboratory (AFCRC, ARDC), to monitor a project with the Research Foundation of Ohio State University. Among the more interesting of the research findings was that "higher noise levels do not create confusion, but do intensify those confusions already inherent between the words in question".
By early 1956 the ICAO was nearly complete with this research, and published the new official phonetic alphabet in order to account for discrepancies that might arise in communications as a result of multiple alphabet naming systems coexisting in different places and organizations. NATO was in the process of adopting the ICAO spelling alphabet, and apparently felt enough urgency that it adopted the proposed new alphabet with changes based on NATO's own research, to become effective on 1 January 1956,[29] but quickly issued a new directive on 1 March 1956[30] adopting the now official ICAO spelling alphabet, which had changed by one word (November) from NATO's earlier request to ICAO to modify a few words based on US Air Force research.
After all of the above study, only the five words representing the letters C, M, N, U, and X were replaced. The ICAO sent a recording of the new Radiotelephony Spelling Alphabet to all member states in November 1955.[27] The final version given in the table above was implemented by the ICAO on, and the ITU adopted it no later than 1959 when they mandated its usage via their official publication, Radio Regulations. Because the ITU governs all international radio communications, it was also adopted by most radio operators, whether military, civilian, or amateur. It was finally adopted by the IMO in 1965.
During 1947 the ITU adopted the compound Latinate prefix-number words (Nadazero, Unaone, etc.), later adopted by the IMO during 1965.
In the official version of the alphabet,[4] two spellings deviate from the English norm: Alfa and Juliett. Alfa is spelled with an f as it is in most European languages because the spelling Alpha may not be pronounced properly by native speakers of some languages – who may not know that ph should be pronounced as f. The spelling Juliett is used rather than Juliet for the benefit of French speakers, because they may otherwise treat a single final t as silent. For similar reasons, Charlie and Uniform have alternative pronunciations where the ch is pronounced "sh" and the u is pronounced "oo". Early on, the NATO alliance changed X-ray to Xray in its version of the alphabet to ensure that it would be pronounced as one word rather than as two,[32] while the global organization ICAO keeps the spelling X-ray.
The alphabet is defined by various international conventions on radio, including:
| 1920 UECU | 1927 (Washington, D.C.) International Radiotelegraph Convention (CCIR) | 1932 General Radiocommunication and Additional Regulations (CCIR/ICAN)[39] [40] | 1938 (Cairo) International Radiocommunication Conference code words | 1947 (Atlantic City) International Radio Conference[41] | 1947 ICAO (from 1943 US - UK)[42] [43] | 1947 ICAO alphabet (from ARRL< | --the ref only says this happened, but doesn't give the code words-->)[44] | 1947 ICAO Latin America/Caribbean | 1947 IATA proposal to ICAO | 1949 ICAO code words[45] | 1951 ICAO code words | 1956 ICAO final code words | 1959 (Geneva) ITU Administrative Radio Conference code words[46] | 1959 ITU pronunciations | 2008–present ICAO code words | 2005–present IMO pronunciations (English) | 2005–present IMO pronunciations (French) | 2008–present ICAO pronunciations | 2018–present NATO pronunciations |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| A | Argentine | Amsterdam | Amsterdam | Amsterdam | Amsterdam | ABLE | ADAM | ANA | ALPHA | Alfa | Alfa | Alfa | Alfa | AL FAH | Alfa | AL FAH | AL FAH | AL FAH | al-fah |
| B | Brussels | Baltimore | Baltimore | Baltimore | Baltimore | BAKER | BAKER | BRAZIL | BETA | Beta | Bravo | Bravo | Bravo | BRAH VOH | Bravo | BRAH VO | BRA VO | BRAH VOH | brah-voh |
| C | Canada | Canada | Casablanca | Casablanca | Casablanca | CHARLIE | CHARLIE | COCO | CHARLIE | Coca | Coca | Charlie | Charlie | CHAR LEE or SHAR LEE | Charlie | CHAR LEE (or SHAR LEE) | TCHAH LI (ou CHAR LI) | CHAR LEE or SHAR LEE | char-lee |
| D | Damascus | Denmark | Danemark | Danemark | Danemark | DOG | DAVID | DADO | DELTA | Delta | Delta | Delta | Delta | DELL TAH | Delta | DELL TAH | DEL TAH | DELL TAH | dell-tah |
| E | Ecuador | Eddystone | Edison | Edison | Edison | EASY | EDWARD | ELSA | EDWARD | Echo | Echo | Echo | Echo | ECK OH | Echo | ECK O | EK O | ECK OH | eck-oh |
| F | France | Francisco | Florida | Florida | Florida | FOX | FREDDIE | FIESTA | FOX | Foxtrot | Foxtrot | Foxtrot | Foxtrot | FOKS TROT | Foxtrot | FOKS TROT | FOX TROTT | FOKS TROT | foks-trot |
| G | Greece | Gibraltar | Gallipoli | Gallipoli | Gallipoli | GEORGE | GEORGE | GATO | GRAMMA | Golf | Gold | Golf | Golf | GOLF | Golf | GOLF | GOLF | GOLF | golf |
| H | Hanover | Hanover | Havana | Havana | Havana | HOW | HARRY | HOMBRE | HAVANA | Hotel | Hotel | Hotel | Hotel | HOH TELL | Hotel | HOH TELL | HO TÈLL | HO TELL | hoh-tel |
| I | Italy | Italy | Italia | Italia | Italia | ITEM | IDA | INDIA | ITALY | India | India | India | India | IN DEE AH | India | IN DEE AH | IN DI AH | IN DEE AH | in-dee-ah |
| J | Japan | Jerusalem | Jérusalem | Jérusalem | Jerusalem | JIG | JOHN | JULIO | JUPITER | Julietta | Juliett | Juliett | Juliett | JEW LEE ETT | Juliett | JEW LEE ETT | DJOU LI ÈTT | JEW LEE ETT | jew-lee-ett |
| K | Khartoum | Kimberley | Kilogramme | Kilogramme | Kilogramme | KING | KING | KILO | KILO | Kilo | Kilo | Kilo | Kilo | KEY LOH | Kilo | KEY LOH | KI LO | KEY LOH | key-loh |
| L | Lima | Liverpool | Liverpool | Liverpool | Liverpool | LOVE | LEWIS | LUIS | LITER | Lima | Lima | Lima | Lima | LEE MAH | Lima | LEE MAH | LI MAH | LEE MAH | lee-mah |
| M | Madrid | Madagascar | Madagascar | Madagascar | Madagascar | MIKE | MARY | MAMA | MAESTRO | Metro | Metro | Mike | Mike | MIKE | Mike | MIKE | MA ÏK | MIKE | mike |
| N | Nancy | Neufchatel | New York | New-York | New York | NAN | NANCY | NORMA | NORMA | Nectar | Nectar | November | November | NO VEM BER | November | NO VEM BER | NO VÈMM BER | NO VEM BER | no-vem-ber |
| O | Ostend | Ontario | Oslo | Oslo | Oslo | OBOE | OTTO | OPERA | OPERA | Oscar | Oscar | Oscar | Oscar | OSS CAH | Oscar | OSS CAH | OSS KAR | OSS CAH | oss-cah |
| P | Paris | Portugal | Paris | Paris | Paris | PETER | PETER | PERU | PERU | Polka | Papa | Papa | Papa | PAH PAH | Papa | PAH PAH | PAH PAH | PAH PAH | pah-pah |
| Q | Quebec | Quebec | Québec | Québec | Quebec | QUEEN | QUEEN | QUEBEC | QUEBEC | Quebec | Quebec | Quebec | Quebec | KEH BECK | Quebec | KEH BECK | KÉ BÈK | KEH BECK | keh-beck |
| R | Rome | Rivoli | Roma | Roma | Roma | ROGER | ROBERT | ROSA | ROGER | Romeo | Romeo | Romeo | Romeo | ROW ME OH | Romeo | ROW ME OH | RO MI O | ROW ME OH | row-me-oh |
| S | Sardinia | Santiago | Santiago | Santiago | Santiago | SUGAR | SUSAN | SARA | SANTA | Sierra | Sierra | Sierra | Sierra | SEE AIR RAH | Sierra | SEE AIR RAH | SI ÈR RAH | SEE AIR RAH | see-air-rah |
| T | Tokio | Tokio | Tripoli | Tripoli | Tripoli | TARE | THOMAS | TOMAS | THOMAS | Tango | Tango | Tango | Tango | TANG GO | Tango | TANG GO | TANG GO | TANG GO | tang-go |
| U | Uruguay | Uruguay | Upsala | Upsala | Upsala | UNCLE | UNION | URUGUAY | URSULA | Union | Union | Uniform | Uniform | or OO NEE FORM | Uniform | YOU NEE FORM (or OO NEE FORM) | YOU NI FORM (ou OU NI FORM) | YOU NEE FORM or OO NEE FORM | you-nee-form |
| V | Victoria | Victoria | Valencia | Valencia | Valencia | VICTOR | VICTOR | VICTOR | VICTOR | Victor | Victor | Victor | Victor | VIK TAH | Victor | VIK TAH | VIK TAR | VIK TAH | vic-tah |
| W | Washington | Washington | Washington | Washington | Washington | WILLIAM | WILLIAM | WHISKEY | WHISKEY | Whiskey | Whiskey | Whiskey | Whiskey | WISS KEY | Whiskey | WISS KEY | OUISS KI | WISS KEY | wiss-key |
| X | Xaintrie | Xantippe | Xanthippe | Xanthippe | Xanthippe | XRAY | X-RAY | EQUIS | X-RAY | eXtra | eXtra | X-ray | X-ray | ECKS RAY | X-ray | ECKS RAY | ÈKSS RÉ | ECKS RAY | ecks-ray |
| Y | Yokohama | Yokohama | Yokohama | Yokohama | Yokohama | YOKE | YOUNG | YOLANDA | YORK | Yankey | Yankee | Yankee | Yankee | YANG KEY | Yankee | YANG KEY | YANG KI | YANG KEY | yang-key |
| Z | Zanzibar | Zululand | Zürich | Zurich | Zurich | ZEBRA | ZEBRA | ZETA | ? | Zebra | Zulu | Zulu | Zulu | ZOO LOO | Zulu | ZOO LOO | ZOU LOU | ZOO LOO | zoo-loo |
| 0 | Jérusalem | Jerusalem[47] | Zero | Juliett | (alt. proposals: ZE-RO, ZERO) | zero | (see table of digits) | (see table of digits) | ZE-RO | zee-ro | |||||||||
| 1 | Amsterdam | Amsterdam | Wun | Alfa | (alt. proposals: WUN, WUN) | one | WUN | wun | |||||||||||
| 2 | Baltimore | Baltimore | Too | Bravo | (alt. proposals: TOO, BIS) | two | TOO | too | |||||||||||
| 3 | Casablanca | Casablanca | Thuh-ree | Charlie | (alt. proposals: TREE, TER) | three | TREE | tree | |||||||||||
| 4 | Danemark | Danemark | Fo-wer | Delta | (alt. proposals: FOW-ER, QUARTO) | four | FOW-er | fow-er | |||||||||||
| 5 | Edison | Edison | Fi-yiv | Echo | (alt. proposals: FIFE, PENTA) | five | FIFE | fife | |||||||||||
| 6 | Florida | Florida | Six | Foxtrot | (alt. proposals: SIX, SAXO) | six | SIX | six | |||||||||||
| 7 | Gallipoli | Gallipoli | Seven | Golf | (alt. proposals: SEV-EN, SETTE) | seven | SEV-en | sev-en | |||||||||||
| 8 | Havana | Havana | Ate | Hotel | (alt. proposals: AIT, OCTO) | eight | AIT | ait | |||||||||||
| 9 | Italia | Italia | Niner | India | (alt. proposals: NIN-ER, NONA) | nine | NIN-er | nin-er | |||||||||||
| . (decimal point) | (proposals: DAY-SEE-MAL, DECIMAL) | decimal | DAY-SEE-MAL | DÉ-SI-MAL | DAY-SEE-MAL | ||||||||||||||
| Hundred | hundred | HUN-dred | |||||||||||||||||
| Thousand | (proposals: TOUS-AND, -) | thousand | TOU-SAND | ||||||||||||||||
| , | Kilogramme | Kilogramme | Kilo | ||||||||||||||||
| / (fraction bar) | Liverpool | Liverpool | Lima | ||||||||||||||||
| (break signal) | Madagascar | Madagascar | Mike | ||||||||||||||||
| . (punctuation) | New-York | New York | November | STOP | STOP |
The ITU adopted the IMO phonetic spelling alphabet in 1959,[48] and in 1969 specified that it be "for application in the maritime mobile service only".[49]
Pronunciation was not defined prior to 1959. For the post-1959 phonetics, the underlined syllable of each letter word should be emphasized, and each syllable of the code words for the post-1969 figures should be equally emphasized.
The Radiotelephony Spelling Alphabet is used by the International Civil Aviation Organization for international aircraft communications.[4] [14]
| 1932 General Radiocommunication and Additional Regulations (CCIR/ICAN) | 1946 ICAO Second Session of the Communications Division (same as Joint Army/Navy) | 1947 ICAO (same as 1943 US-UK) | 1947 ICAO alphabet (adopted exactly from ARRL | 1947 ICAO Latin America/Caribbean | 1949 ICAO code words | 1951 ICAO code words | 1956–present ICAO code words | ||
|---|---|---|---|---|---|---|---|---|---|
| A | Amsterdam | Able | ABLE | ADAM | ANA | Alfa | Alfa | Alfa | |
| B | Baltimore | Baker | BAKER | BAKER | BRAZIL | Beta | Bravo | Bravo | |
| C | Casablanca | Charlie | CHARLIE | CHARLIE | COCO | Coca | Coca | Charlie | |
| D | Danemark | Dog | DOG | DAVID | DADO | Delta | Delta | Delta | |
| E | Edison | Easy | EASY | EDWARD | ELSA | Echo | Echo | Echo | |
| F | Florida | Fox | FOX | FREDDIE | FIESTA | Foxtrot | Foxtrot | Foxtrot | |
| G | Gallipoli | George | GEORGE | GEORGE | GATO | Golf | Gold | Golf | |
| H | Havana | How | HOW | HARRY | HOMBRE | Hotel | Hotel | Hotel | |
| I | Italia | Item | ITEM | IDA | INDIA | India | India | India | |
| J | Jérusalem | Jig | JIG | JOHN | JULIO | Julietta | Juliett | Juliett | |
| K | Kilogramme | King | KING | KING | KILO | Kilo | Kilo | Kilo | |
| L | Liverpool | Love | LOVE | LEWIS | LUIS | Lima | Lima | Lima | |
| M | Madagascar | Mike | MIKE | MARY | MAMA | Metro | Metro | Mike | |
| N | New York | Nan (later Nickel) | NAN | NANCY | NORMA | Nectar | Nectar | November | |
| O | Oslo | Oboe | OBOE | OTTO | OPERA | Oscar | Oscar | Oscar | |
| P | Paris | Peter | PETER | PETER | PERU | Polka | Papa | Papa | |
| Q | Québec | Queen | QUEEN | QUEEN | QUEBEC | Quebec | Quebec | Quebec | |
| R | Roma | Roger | ROGER | ROBERT | ROSA | Romeo | Romeo | Romeo | |
| S | Santiago | Sail/Sugar | SUGAR | SUSAN | SARA | Sierra | Sierra | Sierra | |
| T | Tripoli | Tare | TARE | THOMAS | TOMAS | Tango | Tango | Tango | |
| U | Upsala | Uncle | UNCLE | UNION | URUGUAY | Union | Union | Uniform | |
| V | Valencia | Victor | VICTOR | VICTOR | VICTOR | Victor | Victor | Victor | |
| W | Washington | William | WILLIAM | WILLIAM | WHISKEY | Whiskey | Whiskey | Whisky | |
| X | Xanthippe | X-ray | XRAY | X-RAY | EQUIS | X-RAY | eXtra | X-ray | |
| Y | Yokohama | Yoke | YOKE | YOUNG | YOLANDA | Yankey | Yankee | Yankee | |
| Z | Zürich | Zebra | ZEBRA | ZEBRA | ZETA | Zebra | Zulu | Zulu | |
| 0 | Zero | Zero | Zero | ||||||
| 1 | One | Wun | One | ||||||
| 2 | Two | Too | Two | ||||||
| 3 | Three | Thuh-ree | Three | ||||||
| 4 | Four | Fo-wer | Four | ||||||
| 5 | Five | Fi-yiv | Five | ||||||
| 6 | Six | Six | Six | ||||||
| 7 | Seven | Seven | Seven | ||||||
| 8 | Eight | Ate | Eight | ||||||
| 9 | Nine | Niner | Niner | ||||||
| . | Decimal | ||||||||
| 100 | Hundred | ||||||||
| 1000 | Thousand |
The ITU-R Radiotelephony Alphabet is used by the International Maritime Organization for international marine communications.
| 1932–1965 IMO code words | 1965–present (WRC-03) IMO code words[50] | 1967 WARC code words[51] | 2000–present IMO SMCP pronunciations | 1967 WARC pronunciations | 2007–present ITU-R pronunciations | ||
|---|---|---|---|---|---|---|---|
| A | Amsterdam | Alfa | Alfa | Alfa | AL FAH | AL FAH | |
| B | Baltimore | Bravo | Bravo | Bravo | BRAH VOH | BRAH VOH | |
| C | Casablanca | Charlie | Charlie | Charlie | CHAR LEE or SHAR LEE | CHAR LEE or SHAR LEE | |
| D | Danemark | Delta | Delta | Delta | DELL TAH | DELL TAH | |
| E | Edison | Echo | Echo | Echo | ECK OH | ECK OH | |
| F | Florida | Foxtrot | Foxtrot | Foxtrot | FOKS TROT | FOKS TROT | |
| G | Gallipoli | Golf | Golf | Golf | GOLF | GOLF | |
| H | Havana | Hotel | Hotel | Hotel | HOH TELL | HOH TELL | |
| I | Italia | India | India | India | IN DEE AH | IN DEE AH | |
| J | Jérusalem | Juliett | Juliett | Juliet | JEW LEE ETT | JEW LEE ETT | |
| K | Kilogramme | Kilo | Kilo | Kilo | KEY LOH | KEY LOH | |
| L | Liverpool | Lima | Lima | Lima | LEE MAH | LEE MAH | |
| M | Madagascar | Mike | Mike | Mike | MIKE | MIKE | |
| N | New-York | November | November | November | NO VEM BER | NO VEM BER | |
| O | Oslo | Oscar | Oscar | Oscar | OSS CAH | OSS CAH | |
| P | Paris | Papa | Papa | Papa | PAH PAH | PAH PAH | |
| Q | Québec | Quebec | Quebec | Quebec | KEH BECK | KEH BECK | |
| R | Roma | Romeo | Romeo | Romeo | ROW ME OH | ROW ME OH | |
| S | Santiago | Sierra | Sierra | Sierra | SEE AIR RAH | SEE AIR RAH | |
| T | Tripoli | Tango | Tango | Tango | TANG GO | TANG GO | |
| U | Upsala | Uniform | Uniform | Uniform | or OO NEE FORM | or OO NEE FORM | |
| V | Valencia | Victor | Victor | Victor | VIK TAH | VIK TAH | |
| W | Washington | Whisky | Whisky | Whisky | WISS KEY | WISS KEY | |
| X | Xanthippe | X-ray | X-ray | X-ray | ECKS RAY | ECKS RAY | |
| Y | Yokohama | Yankee | Yankee | Yankee | YANG KEY | YANG KEY | |
| Z | Zurich | Zulu | Zulu | Zulu | ZOO LOO | ZOO LOO | |
| 0 | Zero | ZEERO | NADAZERO | ZEERO | NAH-DAH-ZAY-ROH | NAH-DAH-ZAY-ROH | |
| 1 | One | WUN | UNAONE | WUN | OO-NAH-WUN | OO-NAH-WUN | |
| 2 | Two | TOO | BISSOTWO | TOO | BEES-SOH-TOO | BEES-SOH-TOO | |
| 3 | Three | TREE | TERRATHREE | TREE | TAY-RAH-TREE | TAY-RAH-TREE | |
| 4 | Four | FOWER | KARTEFOUR | FOWER | KAR-TAY-FOWER | KAR-TAY-FOWER | |
| 5 | Five | FIFE | PANTAFIVE | FIFE | PAN-TAH-FIVE | PAN-TAH-FIVE | |
| 6 | Six | SIX | SOXISIX | SIX | SOK-SEE-SIX | SOK-SEE-SIX | |
| 7 | Seven | SEVEN | SETTESEVEN | SEVEN | SAY-TAY-SEVEN | SAY-TAY-SEVEN | |
| 8 | Eight | AIT | OKTOEIGHT | AIT | OK-TOH-AIT | OK-TOH-AIT | |
| 9 | Nine | NINER | NOVENINE | NINER | NO-VAY-NINER | NO-VAY-NINER | |
| . | DECIMAL | DAY-SEE-MAL | DAY-SEE-MAL | ||||
| . | Full stop | STOP | STOP | STOP | |||
| , | Comma | ||||||
| Break signal | |||||||
| ⁄ | Fraction bar | ||||||
| 1000 | TOUSAND | TOUSAND |
Since "Nectar" was changed to "November" in 1956, the code has been mostly stable. However, there is occasional regional substitution of a few code words, such as replacing them with earlier variants, because of local taboos or confusing them with local terminology.