I experimented with using the Excel text-to-speech option. Drove my users crazy no matter how much or how little I used it. Had to add an option to turn off speech on my main control panel and eventually just removed the option AND the speech module. What is that line about "the best-laid plans of mice and men..."?
At the risk of offending the fans of TTS, my opinion is that it should be limited to those situations where they can be added to support greater accessibility for the sight impaired user, i.e. along the lines of screen-reader software. It can be invaluable in that situation.
However, a voice telling users to "Select one of the items in this list" every time they put focus on a list or combo box is intolerably condescending, for example.
A screen reader that can actually read off each of the items to be selected is, again, invaluable for sight-impaired users. Telling them to select one is not.
One of the more interesting aspects of getting the new Northwind 2.0 Showcases (Beginner and Developer versions) into production was meeting Microsoft's accessibility requirements. Subtle things that we normally take for granted can be showstoppers. Gradients of color, outlines on controls (where can I click, where can I not click), and so on are easy to implement, even though they might impact a small percentage of users. To those impacted it is a big deal.
If TTS can be implemented as a pseudo "screen reader", therefore, I can see its value. As a "mood setter", I suspect it would have the opposite impact.
