Otherwise swell, except that I was talking about text SPEED, not volume... I actually have written a slider script with the help of the Fred code.
And when testing I noticed that the ability to scale between 10 and 10 000 milliseconds isn't that bad. However, it really would be good if the slider movement could be changed so that when the slider is at its rightmost position, the delay is 10 ms, and when it is in the leftmost position the delay is 10000 - just for consistency's sake, as the volume sliders work that way too.
A high delay time means a slow text speed and vice versa. I'd like the slider to show the text speed not the delay time...