Why say "tree" for "three" and "fife" for "five"

[Tol3458]

As English is the universal language of aviation, it may seem odd that controllers on Pilot Edge say "tree" for "three", "fower" for "four", "fife" for "five" and "niner" for "nine." After all, how would any who speaks fluent English confuse the words for three, four, five and niner for anything else? The answer lies with the ICAO, The International Civil Aviation Organization, which oversees and codifies the principles and techniques of international air navigation?

The pronunciation of the digits 3, 4, 5, and 9 differs from standard English in order to accommodate different dialects. The digit 3 is specified as tree so that it is not pronounced sri; the long pronunciation of 4 (still found in some English dialects) keeps it somewhat distinct from for; 5 is pronounced with a second "f" because the normal pronunciation with a "v" is easily confused with "fire" (a command to shoot); and 9 has an extra syllable to keep it distinct from German nein 'no'.

Though they are "English" words, the choices were made with the world in mind.The final choice of code words for the letters of the alphabet and for the digits was made after hundreds of thousands of comprehension tests involving 31 nationalities.

[Keith Smith]

Squawk 7 2 7 FIRE!

Can't help but be reminded of this sketch from Black Adder: https://www.youtube.com/watch?v=3WHSkbM9zAU

[HRutila]

Though they are "English" words, the choices were made with the world in mind.The final choice of code words for the letters of the alphabet and for the digits was made after hundreds of thousands of comprehension tests involving 31 nationalities.

They were actually made because VHF radios, especially the older ones, can make distinguishing those numbers very difficult. Comprehension tests may have had something to do with ICAO's application of the FAA's original rules, but pronouncing numbers this way was done well prior to ICAO's existence.

[Tol3458]

Though they are "English" words, the choices were made with the world in mind.The final choice of code words for the letters of the alphabet and for the digits was made after hundreds of thousands of comprehension tests involving 31 nationalities.

They were actually made because VHF radios, especially the older ones, can make distinguishing those numbers very difficult. Comprehension tests may have had something to do with ICAO's application of the FAA's original rules, but pronouncing numbers this way was done well prior to ICAO's existence.

Interesting. And probably true. I remember flying with my father in the '60s in his Piper Comanche, who for a long time never used a headset, and simply used a hand-mike and listened to ATC over the tinny speaker in the plane. Recalling this, I recently took off my noise-cancelling headset to see if I could understand the radio chatter over the engine noise by turning the speaker volume full up. In a word: No. Turning up the speaker volume simply distorted the voices. And the noise itself is simply exhausting.

Noise-cancelling headsets are essential for making flying safer, more comfortable and less draining.