October 02, 2006

One small step backwards

Neil Armstrong, when he made that famous step, put his foot in it. He intended to say "That's one small step for a man, one giant leap for mankind." But stepping out after hours floating in a tin can, Armstrong famously fluffed his line, omitting the intended "a" and saying  "That's one small step for man, one giant leap for mankind." Or at least this has until now been standard lore, accepted even by Armstrong. You can listen for yourself:

But according to the BBC (and others have picked up on this) "new analysis of the tapes has proved Mr Armstrong right after all. Computer programmer Peter Shann Ford used audio analysis software to show that the missing "a" was blotted out by transmission static." We also learn "that an analysis of the audio files downloaded from Nasa's website using GoldWave, a $45 (£24) audio editing program, indicates that the word was spoken but not recorded by Mr Armstrong's microphone."

Given the extraordinary voyage of scientific and linguistic discovery the reporter has obviously been on, and the very high regard we have for scientific journalism in the world's press, there's absolutely no reason we should doubt the new conclusions at all, not even in the tiniest itsy bitsy way. Umm... but uh, well, uhh, how about we take a little lookee anyhow, you know, just to be sure...

The construction of an enormous bronze-friezed arch at the front of Language Log Plaza, in anticipation of Geoff Pullum's triumphal return, means that we can't afford GoldWave, or even a pc to try the free version on. But we can use the wonderful acoustic analysis toolkit Praat, which is free and multiplatform.

Now it just so happens that Armstrong conveniently constructed something that linguists treasure, what we call a minimal pair. He not only said "for X man," where we are interested in the X, but also said "for mankind" shortly after. So we can compare the two, and see if there's any sign of that pesky little indefinite article. The middle layer in the first of the two super technical just like real science pics below is a spectrogram for Armstrong's production of "for X man," and the middle layer of the lower pic is a spectrogram for his "for man(kind)," with the "kind" bit cut off. The top of each pic shows the actual waveform, and the red dots mark where Praat thinks various important frequencies are in Armstrong's voice, a basic frequency called the f0, and various formants.

for man

for man

What do you see in these pics? Well, the first thing to note is that the space between "for" and "man" is as near as dammit identical to the space between "for" and "mankind," the scales on the two pics being the same. So if Armstrong did say "a," he certainly didn't waste any time on it. The second thing to note is that yes, there are differences between the two pics: there's more stuff between "for" and "man" than between "for" and "mankind." But what sort of stuff is it? I'm no phonetician, but I can confidently say it's not a canonical "a," or even a schwa (a reduced vowel sound). It contains three short pulses about 2/100th of a second apart. These could indeed be interference, since there are other parts of the recording with small amounts of similar pulsing. But they could also be noises coming from Armstrong, e.g. some sort of creaking in his voice, perhaps (as Megan Crowhurst pointed out to me) glottalization, a constriction in the back of the throat. It's not at all implausible that such glottalization could be the remnant of a super reduced "a" in running speech. But it's impossible to say whether this is likely on the basis of this sample alone: we'd need to analyze lots more of Armstrong's speech and maybe run some follow up experiments to whether others produced such sounds and whether they were perceivable.

Note also one other caveat: conceivably the "for" could have just run into the "a", so that what's left of the intended "a" is in fact before the interval I have marked as being under question. This would mean that Armstrong did indeed produce an "a," but not in such a way that it could be distinguished by a hearer. A phonetician might look for evidence for or against this, but I'll just leave it, since even if true, it would certainly mean that Armstrong did not produce what he intended, i.e. something that could actually be distinguished from "for man."

So where are we now?
  1. Armstrong may or may not have produced the remnants of an "a," in the form e.g. of slight constriction at the back of his throat.
  2. Armstrong did not produce the sort of canonical "a" he would probably have intended for broadcast back to planet Earth, since that would have yielded more space between "for" and "man" than between "for" and "mankind." At least to this extent, it's clear that Armstrong fluffed it.
  3. If Armstrong produced any vowel sound at all in the space, it must have been covered up by interference. It's possible that what we're seeing is three short bursts of transmission static, but if that is static we're seeing, it hasn't left behind it any trace, on my relatively casual inspection, of a canonical vowel (i.e. despite Praat's guesses as regards good places to put red dots, there are no clear formants in the spaces between the pulses, though there may be some voicing).

I don't believe the BBC report. Maybe there was static, but how does Shann Ford or the BBC know there was an "a" underneath it? I haven't seen Shann Ford's explanation first hand, so I'm in no position to criticize him, But for the moment, I'm skeptical. Hopefully a phonetician, or maybe Shann Ford himself, can clear this up for me.

[Update: I got some (indirect) help from Shann Ford, in the form of his published analysis, and some help from a phonetician. Now you can be skeptical too. Shann Ford, though clearly a smart guy, seems a little out of his depth: he just eyeballed the waveform, and didn't even use a spectrogram, the tool that anybody who'd taken a first course in phonetics would have chosen. He made several unjustified leaps in his analysis, and the bottom line is, whatever you read in the world's press: still no "a". See our follow-ups:
One 75-millisecond step before a "man"
Armstrong's abbreviated article: the smoking gun?
Armstrong's abbreviated article: notes from the expert and
First Korean on the moon]

Posted by David Beaver at October 2, 2006 10:57 PM