Yes but it would require a lot of math and a lot of trial and error. You would have to change the circle aspect and also change the start and end radians for the Circle command to where you want the mouth to start and end at. Attached to this I'll add a radians circle chart so you just plug that in to the Circle command. It both has degrees and radians, the radians are the ones with Pi. You also would have to change the aspect number to make the mouth not part of a perfect circle. The aspect number is the very last number on the Circle command. Here is where you can put everything:
CIRCLE [STEP](column, row), radius%, [drawColor%][, startRadian!, stopRadian!] [, aspect!]