A Microsoft Streets & Trips 2007 blog shows how to get "TurnBeep" functionality in MapPoint and Streets & Trips.
The TurnBeep gives an audible notification of a turn --
"In addition to speaking the next turn instructions the turn beep will alert the driver with a sound at or immediately prior to the turn. The 'ding' can be helpful to tell the driver a) that was the intersection you were supposed to turn on and you just missed it or b) that they have chosen the correct turn."
For more information, see --
Add TurnBeep functionality to S&T