Designing for audible interfaces
- Organize and name functions according to user mental models. This
is important in any design, but doubly important when functions
are described only verbally, and only in context of the current
function. Be sure to examine context scenarios to determine what
the most important functions are, and make them the most easily
reachable. This means listing the most common options first.
- Always signpost the currently available functions. The system
should, after every user action, restate the current available
activities and how to invoke them.
- Always provide a way to get back one step and to the top level.
The interface should, after every action, tell the user how to go
back one step in the function structure (usually up one node in
the tree) and how to get to the top level of the function tree.
- Always provide a means to speak with a human. If appropriate, the
interface should give the user instructions on how to switch to a
human assistant after every action, especially if the user seems
to be having trouble.
- Give the user enough time to respond. Systems usually require
verbal or telephone keypad entry of information. Testing should
be done to determine an appropriate length of time to wait; keep
in mind that phone keypads can be awkward and very slow for
entering textual information.
From: Cooper, A., Reimann, R., Cronin, D.: About Face 3 – The Essentials of Interaction Design, Wiley, Indianapolis: 2007, page 199