Twenty-Six Pegs

Picture a pilot over the sea, a controller on the ground, and a crackling radio. The pilot needs to spell the name of an airfield. She says the letters. The controller hears B, D, E, G, P, T and V, and cannot tell which is which. They all sound like the same short noise, bee, dee, ee, gee, pee, tee, vee, and an error here could be dangerous.

Radio operators had faced this since the early days of wireless. In the Second World War the Allies used a word for each letter: Able, Baker, Charlie, Dog, Easy. It worked for English speakers. But after the war, aviation became international, and a code that only works in English is not enough.

In the early 1950s the aviation authorities began to design a new alphabet. They asked linguists to help; among them was a Canadian, Jean-Paul Vinay. The new words had to be easy to say and to recognise for speakers of English, French and Spanish, with a clear and different sound for each.

They tested many words. Some were dropped because speakers of one language mispronounced them. In 1956 the final list was adopted, and it is still used today by pilots, ships, police, armies and call-centre workers: Alfa, Bravo, Charlie, Delta, Echo, Foxtrot, and on through Zulu. Two of the spellings, Alfa and Juliett, are unusual on purpose, to show French and other speakers how to say them.

Look at the list again. It is twenty-six fixed words in a fixed order, which everyone knows, each with a picture or a sound that is easy to see. That is exactly what a memory peg is. If A is Alfa, B is Bravo, C is Charlie, you have twenty-six places in order, and you can hang any list or any set of steps on them.

So: you already know the order. All you need is a picture for each word. Then you have a second, longer set of pegs, to go with the ten body pegs, and with no building.