Besides the fact that it's now a standard, why do American-English-speaking pilots and ATC say "Niner" instead of "Nine"? None of the other numerals are pronounced in an atypical fashion.

For what was "Nine" being mistaken that resulted in the "Niner" standard being adopted?

  • 12
    $\begingroup$ Not all - only the properly trained ones :-) $\endgroup$ May 20 '15 at 13:54
  • $\begingroup$ Hmm... I'd say the fact that it's a standard is why pilots use it. It also sounds a lot less weird to a native English speaker than the tree/fower/fife stuff. Those just sound like a non-native incorrectly trying to pronounce three, some unknown word, and five, respectively. :) $\endgroup$
    – reirab
    May 21 '15 at 4:36
  • $\begingroup$ It's ICAO standard. And certainly with the US military. Actually using it is another thing. And if you've ever used shortwave to communicate you'd get that big "A-Ha". $\endgroup$
    – radarbob
    Feb 8 '16 at 16:32
  • $\begingroup$ @radarbob Can you elaborate on the shortwave reference? $\endgroup$ Feb 8 '16 at 23:15
  • 1
    $\begingroup$ Due to the nature of shortwave reception can be weak and/or have lots of noise. Speaking phonetically helps tree-mendously. And often we'd have to phonetically spell, e.g. "Whisky Hotel Alpha Tango". $\endgroup$
    – radarbob
    Feb 8 '16 at 23:21

According to Wikipedia:

The pronunciation of the digits 3, 4, 5, and 9 differs from standard English – being pronounced tree, fower, fife, and niner. 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'.

The phonetic alphabet is not a random selection of words. It was created very carefully taking dialects into account, so as not to confuse any of the letter with possible mispronunciations. Although they are "English" words, the choices were made with the world in mind.

As mentioned on the same article:

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.

  • 11
    $\begingroup$ @RockPaperLizard Germany as well. Germans struggle with the English "th", it often comes out as "sri" as mentioned above. This is why it is consistently taught as "tree" in Germany for aviation purposes, when English is used in ATC/(A)FIS communication. The Aviation.SE blog will have a series on stuff like this... we are working on it. :) $\endgroup$ May 20 '15 at 8:57
  • 2
    $\begingroup$ @RockPaperLizard I've known Irishmen who pronounce 3 as "tree". It wouldn't surprise me if the whole country has a similar dialect. $\endgroup$
    – Gabe
    May 20 '15 at 16:00
  • 8
    $\begingroup$ Surely, "niner" helps to distinguish 9 from 5. I'd've thought that most of the time, context would make it obvious whether you meant fire or 5 or whether you were saying 'no' in German or 9. But it's surely as easy to mistake a 9 for a 5 as it is to mistake a B for a D, say. $\endgroup$
    – Au101
    May 20 '15 at 16:41
  • 2
    $\begingroup$ @Au101 This is why they went ahead and dont use single letters by themselves, but have the ICAO alphabet: Bravo and Delta. $\endgroup$ May 20 '15 at 21:42
  • 2
    $\begingroup$ Surely the "niner" dates all the way back to WWII? A lone survivor pilot coming back from the front didn't want anyone thinking he was a German. $\endgroup$
    – DrZ214
    Aug 8 '15 at 0:41

The reasons I've heard behind the pronunciations:

  • Three / Tree:
    Some non-native English speakers have trouble both pronouncing and understanding the "TH" sound. Tree is better pronounced and better understood by all people, regardless of accent.

  • Five / Fife:
    Much of aviation has a military history. On a poorly heard transmission "Five" can sound a lot like "Fire", which is both a military command to "shoot", and an aviation emergency! "Fife" avoids that ambiguity.

  • Nine / Niner:
    German is a commonly spoken language, and "Nine" is "No" in German. To keep it clear that this is a digit and not a negative-reply, "Niner" is distinct from the "Nine"

  • $\begingroup$ I've heard that explosives/demolitions engineers skip "Five" for the same reason, but I can't confirm that with fact, only hearsay. $\endgroup$
    – Steve V.
    May 10 '17 at 20:15
  • 13
    $\begingroup$ There's a joke of a german pilot asking "May I get local QHN?" ATC: "Nine, nine, nine".. "Und warum nein?" $\endgroup$
    – gusto2
    May 11 '17 at 9:36
  • 1
    $\begingroup$ I truly appreciate your answer. Even if partially anecdotal, it provides significant insight. $\endgroup$ May 12 '17 at 5:54
  • $\begingroup$ „nein” is “no” in German. “nine” is only pronounced (almost) the same way. $\endgroup$
    – Michael
    Aug 3 '18 at 7:38
  • $\begingroup$ I've heard explosive users skip 4 to avoid confusion with "fire". "Five" and "Nine" have the same vowel, so the 2-syllable "Niner" helps distinguish those two (as does the soft "f" in "Fife", which is more distinct from "n" than "v" would be). $\endgroup$ Aug 3 '18 at 9:53

The standard answer is that “nine” could be mistaken for German “nein”.

Another possibility is that all the digits have a different vowel (or vowel pair) from each other except “nine” and “five”. Changing “nine” to “niner” adds another vowel sound, which may help distinguish them when radio reception is poor.


"Niner" is spoken for the numeral 9 to avoid it being mistaken for 5.

  • 1
    $\begingroup$ This would be better as a comment once you gain enough reputation. $\endgroup$
    – dalearn
    Jan 17 '19 at 18:26
  • 2
    $\begingroup$ @dalearn, what is your basis for saying this would be better as a comment? It answers the question, and answers are frowned upon in comments. $\endgroup$ Dec 14 '21 at 3:06

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.