MAS.632 Conversational Computer Systems - MIT OpenCourseWare

124 VOICE COMMUNICATION WITH COMPUTERS
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Most telephone-based systems employing speech output involve a process of
explicit user selection followed by a system response often repeated step-by-step
while the user performs several operations. These systems spend a substantial
portion of their time reciting menus. The menus may be hierarchical requiring
the user to traverse several submenus and enter multiple key presses to achieve
the desired action. While it is likely that a hierarchical structure may be well
suited for the novice or occasional user, the experienced user learns the sequences
and, provided the menus are interruptible, never hears much of them; callers are
still often annoyed to key-press their way through the thick layering of commands
to get to the information being sought.
This section presents as a case study a system that took a rather different view
of user interaction. Voiced Mail [Schmandt 19841 was a program developed at
M.I.T. to allow telephone access to electronic mail using speech synthesis. Voiced
Mail provided a streamlined user interface oriented towards experienced users. It
tried to minimize the time and attention required to navigate the user interface
by avoiding automatic recitation of menus. Instead, the application followed a
default sequence of presenting information about each message, then the message
itself. The small number of commands were always active, and the application
was always interruptible.
Voiced Mail applied extensive filtering to messages to remove extraneous information,
made presentation decisions based on the length of each message, and
rearranged message order to simplify presentation. These tasks were performed
to minimize the time and attention required to use the application. Voiced Mail
also employed a repetition strategy to help cope with the vagaries of synthesizing
free-form, human-authored text.
Voiced Mail illustrates some advantages of incorporating multiple speech technologies
into a single application. In Voiced Mail's later stages, recorded voice was
used for generating replies to text messages as the keypad was inadequate to
select between a limited repertoire of precomposed text messages. The synergy
from employing multiple channels for computer interaction and supporting multimedia
databases is a theme to which we will return in Chapter 12.
Flow ofCol
To access Voiced Mail, a user dialed in and logged onto the system using his or her
computer login ID and a password. The application would scan the user's new
mail messages and decide how to present them. A default path was then taken
through the messages; with no additional user input, the system would read each
message in order to the caller. At no point was the user confronted with an
explicit "If you want me to do . . (some action), press a key"; rather, an active
presentation was started, which could be interrupted at any time. There were
places where the system would pause a moment to encourage possible user input,
but if none was detected it would continue reading messages. This was all part of
the strategy of avoiding menus.