Use the prescribed radiotelephony term for the decimal point when transmitting frequencies or other numerical information, according to the applicable procedure.
Global Aviation Communication Reference
GLOBAL AVIATION COMMUNICATION REFERENCE
Aviation Phonetic Alphabet A-Z – ICAO Letters & Number Pronunciation
ICAO aviation phonetic alphabet and standardized number pronunciations for pilots, dispatchers, airlines, air traffic control and worldwide flight operations.
A-Z ICAO alphabet
0-9 number pronunciation
Global radiotelephony reference
Last reviewed15 September 2026
Reviewed byFlytag Flight Operations Team
Reference basisICAO radiotelephony spelling alphabet & aviation number pronunciation
ICAO Radiotelephony Spelling Alphabet
The aviation phonetic alphabet assigns a standard code word to every letter from A to Z. It is used in radiotelephony to reduce misunderstanding when letters, registrations, call signs, waypoints or difficult words must be transmitted clearly over radio.
ICAO Annex 10 specifies spellings such as Alfa and Juliett. These are deliberate international spellings used to support consistent pronunciation across different languages and accents.
Operational note: ICAO phonetics are intended to improve clarity. Pilots and operators should follow current ICAO procedures, applicable national AIP requirements, company manuals and ATC instructions for operational radiotelephony.
ICAO Aviation Phonetic Alphabet A-Z
The table below provides the standard ICAO spelling words with a practical English pronunciation guide for quick reference. Pronunciation spellings are approximate; operators should follow current ICAO and local radiotelephony guidance for operational use.
| Letter | ICAO Word | Approximate Pronunciation |
|---|---|---|
| A | Alfa | AL-FAH |
| B | Bravo | BRAH-VOH |
| C | Charlie | CHAR-LEE or SHAR-LEE |
| D | Delta | DELL-TAH |
| E | Echo | ECK-OH |
| F | Foxtrot | FOKS-TROT |
| G | Golf | GOLF |
| H | Hotel | HOH-TEL |
| I | India | IN-DEE-AH |
| J | Juliett | JEW-LEE-ETT |
| K | Kilo | KEY-LOH |
| L | Lima | LEE-MAH |
| M | Mike | MIKE |
| N | November | NO-VEM-BER |
| O | Oscar | OSS-CAH |
| P | Papa | PAH-PAH |
| Q | Quebec | KEH-BECK |
| R | Romeo | ROW-ME-OH |
| S | Sierra | SEE-AIR-RAH |
| T | Tango | TANG-GO |
| U | Uniform | YOU-NEE-FORM or OO-NEE-FORM |
| V | Victor | VIK-TAH |
| W | Whiskey | WISS-KEY |
| X | X-ray | ECKS-RAY |
| Y | Yankee | YANG-KEY |
| Z | Zulu | ZOO-LOO |
Aviation Number Pronunciation
Numbers are also pronounced in a standardized way to improve radio intelligibility, particularly when frequencies, altitudes, headings, flight levels, squawk codes, times and other numerical information are transmitted.
| Number | Word | Approximate Pronunciation |
|---|---|---|
| 0 | Zero | ZEE-RO |
| 1 | One | WUN |
| 2 | Two | TOO |
| 3 | Three | TREE |
| 4 | Four | FOW-ER |
| 5 | Five | FIFE |
| 6 | Six | SIX |
| 7 | Seven | SEV-EN |
| 8 | Eight | AIT |
| 9 | Nine | NIN-ER |
Special Aviation Pronunciation & Number Usage
Number groups may be spoken according to the applicable aviation radiotelephony procedure. Follow the relevant ICAO, state and operator rules for altitudes, levels, headings, frequencies and times.
How a number is transmitted can depend on whether it represents a frequency, altitude, flight level, runway, heading, time, transponder code or other operational value.
How the Phonetic Alphabet Is Used in Flight Operations
Aircraft Registration
A registration containing letters is transmitted using phonetic equivalents when required for clear identification. For example, the letters A6 are spoken using the applicable number pronunciation followed by the phonetic word for the letter when spelling the complete registration.
Call Signs & Identifiers
ATC may use phonetic letter equivalents when aircraft have similar-sounding identifications or when a call sign, waypoint or other identifier needs clarification.
Flight Dispatch
Dispatchers and operations teams commonly use phonetics when confirming registrations, route identifiers, permit references, airport information and other operational details by voice.
Adverse Communication Conditions
Phonetic spelling is particularly useful when radio reception is weak, there is background noise, speakers have different accents, or similar-sounding letters could create ambiguity.
Why ICAO Uses “Alfa” and “Juliett”
Alfa is the ICAO spelling rather than “Alpha,” and Juliett uses two final t's. These spellings were selected for international radiotelephony so the words can be pronounced more consistently by speakers of different languages. For aviation use, the ICAO forms should be retained in reference material and operational training.
Radio Communication Best Practices
- Speak clearly and at a steady rate rather than rushing the transmission.
- Use standard ICAO phonetic words when letters need to be spelled.
- Use standardized number pronunciation where required by applicable radiotelephony procedures.
- Read back clearances and safety-critical information in accordance with ATC and regulatory procedures.
- Avoid non-standard substitute words that can introduce ambiguity.
How Flytag Maintains This Reference
Flytag reviews this page as an aviation communications reference and compares the spelling alphabet, number pronunciations and radiotelephony notes against authoritative aviation guidance. This page is a quick-reference aid and does not replace current ICAO publications, national AIP requirements, ATC instructions or approved operator procedures.
Aviation Phonetic Alphabet FAQ
Is the NATO phonetic alphabet the same as the ICAO aviation phonetic alphabet?
The commonly referenced NATO phonetic alphabet uses the same internationally standardized spelling words used in civil aviation, including Alfa, Bravo, Charlie through Zulu.
Why is Alpha spelled Alfa in aviation?
ICAO standardizes the spelling as “Alfa” to support more consistent pronunciation internationally. Aviation references should therefore use Alfa rather than Alpha when presenting the ICAO form.
Why is Juliett spelled with two t's?
The ICAO spelling is “Juliett.” The standardized form helps avoid pronunciation ambiguity among speakers of different languages.
Why do pilots say “Niner” for nine?
Standardized aviation number pronunciation is designed to reduce misunderstanding over radio. “Niner” is the recognized pronunciation used for the digit 9 in aviation radiotelephony.
How are the numbers 3, 4 and 5 pronounced in aviation?
Common aviation pronunciation guides render 3 as TREE, 4 as FOW-ER and 5 as FIFE to improve intelligibility over radio.
When should pilots use phonetic spelling?
Phonetics are used when identifying aircraft and when single letters, groups of letters or difficult words need to be transmitted clearly, particularly when communication conditions could cause confusion.
Authoritative references: This page is aligned with the ICAO radiotelephony spelling alphabet in Annex 10, Volume II, and the FAA Aeronautical Information Manual phonetic alphabet guidance. Operators should consult the latest applicable ICAO publications, national AIP and company procedures for operational use.
ICAO Annex 10, Volume II — Radiotelephony Spelling Alphabet
FAA Aeronautical Information Manual — Radio Communications & Phonetic Alphabet
ICAO Annex 10, Volume II — Radiotelephony Spelling Alphabet
FAA Aeronautical Information Manual — Radio Communications & Phonetic Alphabet
