Some letters of the alphabet sound very similar, like 'M' and 'N', or 'B' and 'P'.
When police officers spell out names or number plates over a radio, they need to be heard clearly. To avoid confusion, they use words instead of letters to spell things out.
Every letter has its own special word. Together, these words make up the 'radio', or 'phonetic', alphabet.
Game: See how long it takes you to learn the radio alphabet. Once you've learnt it off by heart, try learning it backwards.