Spelling Alphabets: How to be Clear over the Radio

If you’ve ever found yourself asking, “How do you spell alphabet?” or “How to spell alphabet?”, during a crackly phone call where the letters “B”, “D”, and “P” collapse into the same sound, this article is perfect for you! You’ll learn that to avoid these misunderstandings, many professionals (but also civilians) rely on the International Radiotelephony Spelling Alphabet, a standardized form of alphabet spelling that converts single letters into unmistakable words.

Before we go further, here’s a handy tool you can play with right away: our NATO phonetic alphabet translator, which you can use to convert any word into code words in seconds.

A spelling alphabet (also known as radio alphabet, radiotelephony alphabet, or voice procedure alphabet) is a curated set of words that represent letters when you speak them out loud. Instead of saying “B” and hoping the listener doesn’t hear “D”, you say “Bravo”; instead of “P”, you say “Papa”; and instead of “D”, you say Delta. These words were chosen because they sound distinct even when the audio is messy.

This feature is the cornerstone of how to spell letters of the alphabet clearly over voice channels: you trade fragile single-letter sounds for sturdier, more recognizable whole words. It’s not just for pilots and soldiers; any time you dictate a password, a surname, a serial number, you’re living in the world of how do you spell letters of the alphabet without visual info.

If you click on our article: “NATO Alphabet History”, you’ll learn the history behind the standardization of spelling alphabets and why it matters. For decades, different militaries, companies, and services invented their own code words, often with little coordination, because early telephone networks and radio links rendered speech somewhat unclear.

British Army signalers employed early forms of spelling alphabets in the late 19th century. They refined them in the early 1900s, initially focusing on the letters that caused the most confusion. At first, a partial alphabet was used for the most problematic letters, such as “Ack” for A and “Beer” for B. These terms have remained famous, particularly thanks to the expression “Ack-Ack”, which refers to anti-aircraft artillery.

Later, the pressure of World War I and the rapid growth of field communications led to broader adoption. Thus, each branch of the military and each telephone company (such as AT&T or Western Union) ended up developing its own codes. In 1959, a study identified over 200 different spelling alphabets for English, totaling about 1,600 different words.

Modern international aviation has posed a challenging question: how do you maintain reliable communications when pilots and controllers speak different native languages and transmit through noisy radios? The answer became the ICAO spelling alphabet, also known as the International Radiotelephony Spelling Alphabet and widely recognized as the NATO phonetic alphabet.

The ICAO (International Civil Aviation Organization) selected and tested code words so they stay intelligible across accents, speed, stress, and interference, which is precisely why you’ll hear Alfa, Bravo, Charlie, Delta… Zulu in cockpits, control towers, ships, and many radio networks.

Here’s the NATO correspondence table (ICAO code words stable since 1956):

Thus, if you want to spell your name, such as “Mary”, during a phone call with a bad connection, you can use this spelling alphabet and say: “M as Mike”, “A as Alfa”, “R as Romeo”, and “Y as Yankee”.

You’ll often see the ICAO spelling alphabet described as a military spelling alphabet, essentially because the armed forces played a significant role in shaping and stress-testing it under real operational conditions. However, the broader logic behind the international radiotelephony spelling alphabet is less about the military itself and more about voice procedure, also known as the disciplined way people speak when clarity is more important than conversational ease.

Indeed, the effectiveness of a radio alphabet relies on acrophony, meaning each code word begins with the letter it represents. However, the procedure does not stop at letters alone. Numbers also require special handling to avoid ambiguity, which brings us to common questions like: Why do People say “Niner” Instead of Nine? Want to know the answer? Click on the hyperlink!

The same need for precision existed long before the advent of modern radios. In maritime operations, for example, flaghoist spelling alphabets were used to send visual signals between ships. Yet, the instructions for raising those flags were often transmitted verbally through acoustic tubes or sound-powered telephones (once again making clear, standardized code words essential).

We hope that thanks to our article, the next time you catch yourself asking “how do you spell alphabet “ or “how do you spell letters of the alphabet”, you can answer like a pro. Remember that whether you refer to it as the spelling alphabet, the ICAO spelling alphabet, or a military spelling alphabet, the underlying principle remains the same: you want to remove ambiguity from spoken language so the message arrives intact to the receiver the first time.