Hearing the difference between the digraph sounds /sh/ and /ch/ is challenging for many dyslexic students. To further complicate, some adult student come from a French-speaking background, in which the CH sounds like /sh/.
Here are some steps to take:
1. Use movements and decibel levels to differentiate between the two sounds.
For CH, the keyword is chop, with a chopping movement. Make the /ch/ sound with some force, as you make the chopping movement.