This question comes from a Japanese friend: “How do you say CH in Michigan and Chicago?”
The CH in Chicago and Michigan is pronounced as an SH sound.
To make an SH sound, be sure that your tongue is in the middle of your mouth and that your lips are rounded. The air keeps moving for the SH sound.
The CH sound is make by touching the back of your front teeth. Then it moves to the middle of your mouth. The air flow quickly changes from stopping to moving. The CH is a combination of T+SH.