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.