All right, I'm going to start this particular utterance again
by segmenting it.
This is a very short segment, probably just a single segment
here.
For the time being there's no indication--
This is a speech spectrogram.
A speech spectrogram is a visual display
of the energy in the speech wave in terms of frequency and time.
This film examines the performance of an expert
spectrogram reader.
Now the first path's segmentation is done.
I'm going to do it here.
There is obviously a [INAUDIBLE] and it's--
I'm going to say it's a "w."
It's very easy to see that the second formant is climbing.
There's a [INAUDIBLE] here with the second and third formants
going together.
I have to say this is an "e."
There's another nasal here.
I'm going to say again it's an "e."
There's another segment here followed by a nasal at the end.
In 1971, Dr. Victor Zue began to study spectrograms.
His goal, to learn to identify the phonetic content
of an unknown utterance from a spectrographic display.
Since 1971 Dr. Zue has devoted about an hour a day
to learning to read speech spectrographs.
--appears to be coming out of an--
Altogether he has spent between 2,000 and 3,000
hours developing this skill.
In 1977 and 1978 we studied Dr. Zue's his ability
to identify phonetic segments from spectrograms of utterances
which were unknown to him.
F1 is around 500 hertz.
F2 is around 1,500 hertz or so.
I would say it's probably an [INAUDIBLE]
before an [INAUDIBLE].
All of them going down to this particular voice fricative.
I would say this is probably a [INAUDIBLE] before [INAUDIBLE]..
Path 3 is lower than 2,000 hertz.
These two are very close together.
I would say there is probably a schwa.
And given that there appears--
they appear to be separating again.
I'm going to say there is a schwa here.
This particular transition indicates
that it's probably an "a" and with the possibility
that it being an "e."
This [INAUDIBLE] is definitely an "a."
Again, here we see the possibility
of an [? r-color, ?] either "r" [? "ruh" ?] or just
a [INAUDIBLE].
And going back to the last nasal,
which with the transitions all coming down,
I would say it's probably an [? "n." ?]
Dr. Zue was presented with over 40 spectrograms.
Included were normal English sentences,
semantically anomalous sentences,
and sequences of connected words and nonsense words.
To evaluate Dr. Zue's performance
we asked three phoneticians to listen
to the original utterances and produce
phonetic transcriptions.
Dr. Zue's labeling agreed with the phoneticians on 80% to 90%
of the segments.
I think the only place that I might
want to add something would be saying this is probably
[INAUDIBLE].
This is probably-- a possibility of a [INAUDIBLE]..
What do you think the utterance is?
The first word is "winning."
"Winning is never"-- at the end I have, "for him."
So "winning is never a" something "for him,"
and I'm stuck here.
"Per-- pretty-- pretty"--
something.
"Pretty [? had"-- ?] I give up.
"Thing."
"Pretty thing for him"?
"Winning is never a pretty thing for him."
Pretty thing for him.
What a weird sentence.
Analysis of the experts' performance reveals that
spectrograms are read in two steps:
segmentation and labelling.
The purpose of the segmentation process
is to divide the speech wave into units that correspond
to phonetic segments.
The main cue to segmentation is an abrupt spectral
discontinuity.
In some cases when an abrupt change is not observed,
duration is used to determine whether one or two segments
exist.
All right.
First of all, I'm going to segment
this particular utterance into as many syllables as I can find
and basically using the spectral change
as a parameter for making-- marking the boundary.
Some of the places, for example, here is awful weak.
It's kind of hard to determine.
So for the time being I'm going to put a marker here and here,
here, and here.
All right.
The formant motion-- the second formant motion
indicates that within this segment
it's going through sort of maybe two different steady states.
So there's a possibility of an additional segment.
Here for this particular one, I see that first of all,
there's almost a discontinuity here,
and also the third formant is rising.
So I'm going to postulate that there
is an additional segment there.
There is intensity-- sharp intensity difference,
a couple with a change in the second and third formant
so I'm going to put these boundaries there.
There's again a--
Dr. Zue is able to detect the existence of more than 95%
of all segments.
Once the segment boundaries have been identified,
the labeling process begins.
Dr. Zue's ability to accurately label phonetic segments
is a unique and complex skill.
There is something here.
It's either a-- it's a very weak fricative,
or it's going to be a unreleased stop.
Something like that.
Here is another stop and formant transition again indicate
that perhaps this is a labial.
And we again have a voiced stop because of the short voicing
onset time.
So I'm going to guess that it is a "b."
We're going to leave that at that for the moment.
Here I see, again, a vowel gliding into something.
The third formant is going way up
and the second formant is coming down,
and the proximity of these two formants,
first and second formants indicates that this is probably
a lateral [INAUDIBLE].
Many segments, such as vowels, have
characteristic spectral patterns that
are recognizable over a wide variety of contexts.
One example is the spreading form and pattern
of the diphthong ay.
Reduced vowels can be identified by their short duration.
When a vowel cannot be identified by a characteristic
pattern, formant frequencies may be measured.
Nasal consonants are recognizable by sharp amplitude
drops.
r's are identifiable by a third formant
that drops below 2,000 hertz.
Quite often a segment is influenced by the context
in which it occurs.
For example, in the utterance, "Tom stole a butter plate,"
we observe that the "t" in initial position
is relatively long with pronounced aspiration.
In an initial s-t cluster, the aspiration
is no longer observed, and in "butter" it becomes a flap.
In final position, the "t" is often unreleased.
By studying thousands of spectrograms
Dr. Zue has learned to recognize the influence
of phonetic context and the operation
of phonological rules.
Here is an example of the application of this knowledge.
This is a strong fricative with energy well about 4,000 hertz.
So is this one.
So I would posulate at least they
have the same place of articulation,
and I think this one probably is an "s" because it's very
strong, very high in frequency.
This one is shorter than that one.
It's possible that this one is a "z."
However, it's also possible that this particular fricative
is in a cluster with this particular stop here,
which will reduce the duration of the fricative.
For lack of any further information
I'm going to say this one is either
as short "s" because it's a cluster, or it's a "z."
Once labeling was completed, Dr. Zue
was asked if he could read off the utterance, something
he does not often do in his own work.
OK.
Let me try to string the phonemes into words.
I propose the word "yesterday" followed by the word "bill."
That's probably an [INAUDIBLE] or I'm missing a segment here.
That's either "the" or "va," and I probably
would say it's "the."
Yesterday Bill saw the--
[INAUDIBLE] Goodyear blimp."
[INAUDIBLE]?
Yeah.
Good-- Goodyear blimp, yeah.
"Yesterday Bill saw the Goodyear blimp."
In the 30 years since the invention of the speech
spectrograph there have been several attempts
to teach people to read spectrograms.
Although some encouraging results were achieved,
the general conclusion of this research
has been that spectrogram reading is not
possible because of the variability inherent
in fluent speech.
In this film Dr. Zue has demonstrated
that despite the difficulties involved,
such a skill can be acquired.
"Winning is never a--
winning is never a--" this is probably "for him."
So "winning is never a something for him."
Pretty-- pretty thing for him?
Pretty thing for him.
What a weird sentence.