“Until recently, voice recognition required each user to
train the system to recognize his or her particular speech
patterns. Like most other software, however, voice recognition
improves, given faster processors and more memory. Recent
products reduce training time dramatically. Speaker-independent
software eliminates training entirely. To achieve highly
accurate speaker-independent recognition with moderate processing
requirements, designers must limit the context and vocabulary of
the application. For example, a car needs to recognize only a few
dozen words, including “temperature”, “radio”, and the numbers
needed to select a station.”
“Lernout & Hauspie (http://www.lhsl.com/), a leading
supplier of voice software, supplies speech engines for
applications as simple as these, as well as far more complex ones.
According to Klaus Schleicher, a director of product management at
L&H, the simplest speech engine provides speaker-independent
recognition of up to 100 words, but requires less than 200K of
memory. L&H offers a more-powerful speech engine that can
recognize up to 1,000 words, again without training. This engine
requires 2MB of memory and can run on a 200MHz processor. This
hardware costs a bit more, but is still easily obtainable for $30
today, and that price will drop over time. The larger vocabulary is
suitable for applications such as a TV set-top box that can be
programmed by speaking the name of a show or a hand-held PDA that
can manage calendars and address books via voice.”
“Composing arbitrary text, such as an e-mail message, requires a
much larger vocabulary. For this purpose, L&H has a speech
engine with a 20,000-word vocabulary–twice as large as the average
adult’s. This engine requires some training, but only about five
minutes per user. Even this large vocabulary doesn’t require a
full-blown PC or server; the company has demonstrated it using a
200MHz StrongArm processor and 32MB of memory. This speech engine
could be incorporated into a webpad, allowing users to compose
e-mail and other documents without using a keyboard.”