Sometimes words just have to be spelled for others. I’ve been on phone conversations where the person on the other end is spelling for me and it’s painful. “Was that a ‘b’ or a ‘p’?” Sometimes they’ll try on the fly to use words with the beginning letter trying to convey the letter: “B as in boy”. Then they’ll get stumped mumbling while they think desperately for ‘k’ words… ‘ketchup’. Okay, but is that really ketchup or catsup? Now think how much easier spelling is on a phone than over a poor quality radio channel. What we say, and how we say it is the key to our brain’s ability to error correct human speech. It’s a solved problem that was built into radio etiquette long ago.