This engine was originally made by Ax0lts. Differences: Having multiple letters with the same mouth shape will increase the exposure of the shape. Including symbols without a designated shape will also increase the exposure. This allows for the creation of more varied timings. The costumes themselves now have a different naming scheme: A prefix of N or P (to represent the Negative and Positive variants of the shape) joined with the string of letters that use them. For example, the project will use the costume "Paei" when displaying a, e, or i with a Positive expression. When I was remastering SpriteON's Scene for T.U.B. (https://scratch.mit.edu/projects/958163554) The majority of the costumes that couldn't be optimized were the mouth costumes, since each one was uniquely suited to the specific position of the character, and what they were saying. I knew that I would want to make a Lip Sync Engine, and to my surprise, there was already an official one linked in the T.U.O.T.U.B. studio. This upgrade to the original engine is certainly a step in the right direction, but it'll never reach the level of complexity that the custom mouth costumes had. My new animation kit is capable of creating layers that can use Scratch's blocks, so it'll be a cinch to make mouth animations with varied position, size, and rotation, but even that isn't enough to match the animation I was remastering, because those costumes could move DURING the animation, as well as squash and stretch for better inbetweens. So for the future, I may try to develop an even more powerful engine that can accomplish all of these things.