A user conducts a telephone conversation without speaking. It does this by
moving the participant in the public situation to a quiet mode of
communication (e.g., keyboard, buttons, touchscreen). All the other
participants are allowed to continue using their usual audible technology
(e.g., telephones) over the existing telecommunications infrastructure.
The quiet user interface transforms the user's silent input selections
into equivalent audible signals that may be directly transmitted to the
other parties in the conversation.