Hey!
STM audio clips and STM sound clips are actually different things. Sound clips are the same as auto clips, but you can call them with a tag, so I thing that's what you're looking for. (There's a typewriter example in there that puts a "ding" sound when return is pressed)
Would it be possible to tell me the exact effect you want your text to do? Even before I add quads to auto clips/sound clips character list, the effect you're after might already be possible.