From: smith@sctc.com (Rick Smith)
Newsgroups: comp.ai
Subject: Re: Voice Recog. on Desktop
Date: 13 Apr 92 15:25:31 GMT
Article-I.D.: sctc.1992Apr13.152531.20065
Organization: SCTC

I'm not trying to say speech recognition is impossible, just that doing
a _good_job_ for arbitrary applications is much harder than most people
understand. If you're used to state of the art speech recognition, then
you probably don't mind the the shortcomings. If you have a specialized
application, then you can adapt your speaking style to the requirements
of speech recognition. However, that's _not_ the same as generally useful
speech recognition.

For example, I hear people talk about "real" computerized dictation
machines. I would expect a "real" dictation machine to take speech at
normal dictation rates. People who dictate can't stand to be limited
in speed. They talk as fast as possible to get their ideas out and to
get the chore of dictation over with. 30-40 words a minute with
pauses between words is just too slow.

Now, to respond to glew@pdx007.intel.com a.k.a. Andy Glew:

rs> I think you'll always need the DSP or the computer will have to run a
rs> sort of "half duplex" where it either does useful work or it listens
rs> to what you're saying. Listening will be a fulltime job.

>No. You can take a lot of interrupts per second on a fast processor.
>The digitized sound can be recorded to a relatively small buffer by
>DMA - it's only about 45K bits/second, less if prefiltered (even by an
>analog filter) - and a 100 Hz interrupt should be fine for doing the
>DSP.  

I'm not concerned about interrupts, I'm concerned about recognition.
From what I understand, speech systems today are "applications" on
workstations, that is, you either run your speech recognizer or you
run your spreadsheet. We can offload things onto a separate card, but
then you're putting an extra workstation-quality processor in your
workstation, just to handle speech input. Maybe that's reasonable, on
the other hand, maybe the tail is wagging the dog.

>Why NVRAM?  Why not just plain simple RAM?

So that you don't lose your speaker adapted patterns when you turn the
power off. Yeah, you can use RAM and then write it back onto your hard
disk, but that means that you've got that much less RAM for doing real
work. If you're going to have a continuously available real time speech
subsystem, then you have to set aside resources for it. You can replace
NVRAM with RAM and hard disk if you want.

rs> Discrete speech means - that - you - talk - like - a - computer - when
rs> - talking - to - a - computer. That's slower than the way real people
rs> talk, so it doesn't compete with normal dictation. 

>Bullshit. First, I don't have a secretary to take dictation. I would be quite
>happy to pause for a fraction of a second, if it meant that I could
>enter text without using a keyboard.

I respectfully disagree. As I pointed out in my opening remarks, most
people who do voice dictation treat it like a chore that must be finished
as quickly as possible. Pauses between words and artifical slowdowns
in the process are technological warts that make it unattractive to
people who aren't charmed by the technology.

>Second, it will not be discrete speech much longer. Nuff said.

Yeah, we said that fifteen years ago, too.  We delivered a continuous
speech recognition system to Rome Labs in about 1976. We figured we'd
make it commercial promptly thereafter. "Not much longer" was lots
longer than any of us thought. Continuous speech is a fundamentally
more difficult problem. As has been pointed out, my knowledge of such
things is dated, but it's still true that continuous speech requires
a completely different approach, and all alternatives are difficult.

rs> There are a whole bunch of other issues, too, concerning errors and
rs> how it "adapts to the speaker" without doing anything damaging.

>Once again, they seemed to have error handling down pretty well - you
>say "oops", and the software displays a menu of "sound alike" words.

This style of error handling works in some situations but not in all
situations. The style assumes that the system is providing interactive
feedback indicating what it heard. This is not a valid assumption for
general purpose speech recognition. I seldom see people echoing each
others' words during a conversation in order to verify speech
understanding; this makes it hard to focus on the content of the
words.  More often I see conversations proceed quite a distance before
a misunderstood word is identified and corrected.

>Finally, just think of the market in those "Press 1 to get sales" type
>phone answering systems. Wouldn't you prefer to hear "Welcome to XYZ
>corp. Do you wish to call sales or service?" and replay "sales"?

There are many current and potential specialized applications like
this that are perfect for speech recognition systems. I believe this
is where speech recognition belongs. We were doing speaker independent
systems like this fifteen years ago.  But success in such applications
doesn't say anything about applicability to "general" speech
recognition.  These are very specialized and rely on highly structured
speech. That's why they're so appropriate.

The big differences between speech recognition "then" and "now" seem
to be in the speed and cost of the platforms. Things are faster and
cheaper now. This means that a speech system can process a larger
vocabulary of discrete words in almost real time.  Part of this is
also attibutable to better algorithms for organizing large vocabulary
databases. Lower cost means that it will be worth using in a broader
range of applications.

>My personal opinion: speech technology is much more useable than the
>so-called "pen computers". There are applications even for the current
>primitive levels. Speech will probably ramp up quicker than pen
>computers, maybe even quicker than video on computers.

I haven't used pen computers, but I can believe that they suffer from
many of the same shortcomings. Both depend on input via pattern matched
expressions. Both will always be more expensive than keyboards. I suspect
that cheap will win. My mom made me take typing in high school. Both of
my kids learned the keyboard before preschool. It's just about time to
teach my first grader touch typing.

Rick.
smith@sctc.com         arden hills, minnesota