In my last Spanish class, my teacher made us do something rather odd. We were practicing saying new words and sentences aloud, and she was not happy with our pronunciation. So we were told to put our pens or pencils in our mouths.
Our teacher explained that having a pen in our mouths would make us focus on what we were saying and enable improved pronunciation. She seemed to think it was a well-established technique for improving speech, but I’ve done a quick search and can’t find any research to back this up.
Personally, I found this unhelpful as I was more focussed on the pen not falling out of my mouth than what I was saying! I wonder if the teacher at Spanish lessons in Chicago does the same trick?