Hi!
Thanks for your amazing work!
I was able to set the engine to Google by clicking the pencil in the "Tasker Commands (Unavailable): With PocketSphinx Engine". By clicking it, a dialog shows up which has two buttons, and through one of them, I can easily set the engine to Google.
However, I tried setting it back to PocketSphinx, but I wasn't able to. I finished up having to clear app data...
Again, congrats for this nice job!