How to change speed of Typewriter effect WITHOUT keyframes?

You can tie the typewriter effect to an audio track in After Effects by converting the Audio to Keyframes, then using an expression to reveal the letters as the audio passes a threshold. 

Unfortunately, this can only be done by converting Audio to Keyframes, so the workflow does not allow you to create a MOGRT that lets you easily follow an audio track in Premiere Pro.

I do this all the time in After Effects. I wish I could have given you an easier solution. You’re going to still have to keyframe things in Premiere Pro.

Here’s a Quick Tip video I produced a while ago. It ties audio to position, but you could easily tie a text animator using the same ideas.

You could apply an expression to the slider which increases your slider value over time without the keyframes.

Example:

var dur = 3;
linear(time,0,dur,0,100)

If you apply this expression to your slider, it will increate the slider value during the first three seconds of the comp from 0 to 100.

Now replace the 3 by another slider, say "duration" and then you can control with that slider how long your typing animation should last.