Is there a way to control how quickly an audio variable is played back? For example, we have a confirmation code being played through an AudioVariable where the format is "Spelling characters" and we would like to have the characters played either slower or with more time in between each character. How can this be accomplished?

Are you setting the inflection field for the audio variable ? You can select falling inflection or raising inflection.

We are setting inflection, but my question is not about inflection.

My question is can I put space in between the speaking of each character? For example, when given the string "3D8CX" ideally I would like to have it do the following:

play the "3" wav file
wait 500ms
play the "D" wav file
wait 500ms
play the "8" wav file
wait 500ms
play the "C" wav file
wait 500ms
play the "X" wav file

You can try adding silence in between the characters.

But unless your framework somehow supports that, I really can't, because I don't control the VXML that's being created, your framework does.

I'm hoping you can tell me there either is or isn't a way that this can be done with the Dialogue Designer framework. And, if there isn't a way, I'd like to suggest that there be a way. (Maybe there already is in OD 6, idk).

FYI, I tried a hack of adding spaces in between the characters that are being spoken, but it had no effect on the spacing between characters.

And when I say below that "it had no effect on the spacing between characters," I mean that I gave an AudioVariable the value "X Y Z" but characters are still spoken one right after the other (same as if it were "XYZ") without any pause in between characters.

You cannot do this with the standard phrases. It will not recognize the space as silence. You need to use your own phrases and explicitly add the silence phrases in between.

I think I may have not been explicit enough in saying that these strings of characters are built at runtime and are unique every time, which is why I'm using an AudioVariable.

Would your suggested solution of using "your own phrases and explicitly add the silence phrases in between" remain the same given this that the string to be played is dynamic, or would you suggest some other solution?

There is no easy way to do this. You can alter the actual wave files with some silence at the beginning or end of the clip, but then the files have that silence everywhere. The other option is to customize your localization bundle.
If you use the localization bundle provided by us, when we convert the variable to a set of wave files, there is no place for a developer to inject any custom behavior.