You can use audio2face to generate blendshapes, and it will also generate a sample mesh of every blendshape, but I would like to be able to test the blendshapes by being able to adjust the weights.
For example, on Skeleton you can adjust bone rotations to move legs etc, but for blendshapes it looks like you can have the Skeletal Animation panel reference a SkelAnimation prim, but I could not see how to look at and adjust the blenshape weights for SkelAnimation prims. So I had to edit the USD file and look at the array of blendshapes by hand to work out which number to adjust. Rather tedious and error prone. Is there a better way?
Step 1: You can select the Skeleton prim and it will identify a SkelAnimaton prim that it previews.
Step 2: You can click on the referenced SkelAnimation prim. Looking at the raw properties, you can see there is blendshape data, but its not visible and you cannot edit it.
Step 3: You can edit the USD file and look for the SkelAnimation node. If you change the weights and save the file, then you can see the impact of the weight changes.
The left eye at 50%.