October 03, 2006

Armstrong's abbreviated article: the smoking gun?

Following our comments earlier on the Small Step saga, I learned from historian Prof. James Hansen, author of the standard biography of Neil Armstrong, that Peter Shann Ford's paper is publicly available. Shann Ford has on the website of his company in html and pdf form. Wonderful! I wish everyone was so  open and diligent!

Ford's waveformIt turns out that Shann Ford's analysis is based solely on the waveform, not on spectrographic analysis. Neither has he performed any special clean up of static or signal processing: he looked at the same thing as Mark and I did, but minus the spectrograms. His main evidence is the figure on the left which he say illustrates "a magnification of the sound wave between the minimum point of decay of "for" at 0.136 seconds and the point of onset of"man" at 0.171 seconds. This 0.035 second sound wave is the elusive "a" - thirty-five thousandths of a second in duration."

Shann Ford goes on to say: "This 0.035 second sound wave is consistent with the sound made in the lingual (tongue) buccal (mouth) labial (lips) transition from the terminal consonant "r" in "for" to a vowel "a" to the introductory "m" in "man". It is not consistent with the sound made in the lingual-buccal-labial transition from the terminal "r" in "for" directly to the introductory "m" in "man", as in "for man"."

Further, we learn that "In the transition from "for" to "a" to "man" the tongue is curled into the terminal "r" of "for" and uncurls for the "a" before the lips close for "m" in "man" creating a pressure wave consistent with the 0.035 second sound wave [in the figure].

In the transition from "for" to "man" (as in the statement "for man") the lips close for the "m" of "man" while the tongue is still curled for the "r" of "for" precluding the creating of the pressure wave consistent with the sound wave of "a"."

None of this is unreasonable. But it's not terribly conclusive either. What Shann Ford claims to have seen is not a smoking gun, but a waft of air as Armstrong reached for the holster. Whether that is indeed what Shann Ford has observed, is not clear, and we have no evidence at all that Armstrong ever fired a bullet. At best, given the timing issues I alluded to in my last post, he probably fired a blank.

Now, as I have to switch to commuter mode, I'll limit myself to a few questions:
  1. Is .35 ms a reasonable length of time for a "sound wave" generated by uncurling of an [r]?
  2. On the spectrogram the first .35 ms of the interval in question does not appear interestingly distinct from what follows: not having the spectrogram available, he has probably chosen the onset point of "man" somewhat arbitrarily. Is there any reason to say that there is a special acoustic feature in the specific .35 ms region Shann Ford identifies?
  3. Even if there was some tongue gesture as Shann Ford describes, is that any reason to say that the "a" followed? Even if we were convinced that the unfolding of the tongue occurred in anticipation of an intended "a", it doesn't follow that there was an "a", only that Armstrong intended to produce one. But we already knew that. He spent several hours rehearsing!
  4. Even if the pulses of energy observed in the spectrograms in our earlier posts were interference (and Shann Ford apparently thinks one of them is a tongue movement, and the others are interference), that still doesn't explain why there is no trace of a vowel-like production in the gaps between the pulses. So if there was an "a", why was it so short (taking no extra time than a transition from "for" to "man" would anyway), and where did it go?
So far, then, I must respectfully remain unconvinced that Shann Ford has actually discovered anything newsworthy. I want to hear more from professional phoneticians before I go any further. But I do think it's neat that Shann Ford tried to apply readily available scientific tools to an old problem. Maybe he or the media didn't realize that there are professionals trained in the use of such tools? And if not, whose fault is that?

Posted by David Beaver at October 3, 2006 07:37 PM