When I present about the workshops, people often ask how I support students with limited verbal skills. Here are three examples of tools I've used or am using.
"Setting / Character / Plot" is a chart for one of my reading groups. In the session, a student with developmental and emotional needs feels more comfortable writing out ideas than sharing aloud (often asking that no one watches while they write). I created this chart for the group to fill out together at the start of every session, giving all the readers in the group an opportunity to share their knowledge of the story and review it as a whole rather than putting any one of them on the spot.
"Idea Board" is a space for a poet with limited verbal skills, but who is often more regulated while drawing and writing. The poster paper's size gives them the opportunity to share their thoughts and contributions with the whole workshop while remaining more grounded and engaged.
"Movement Wall" is for a poet who uses a device to communicate. During a specific movement activity I set up this world wall for them to go and tap (currently working to get the words programmed in) like they would their device to make their choice. This is also a nice visual cue for poets in the group who, while able to verbally communicate, might have difficulties coming up with movement ideas.
These are just a start and have had various successes and failures, if you test these out I'd love to hear how they work in your groups and how you've tweaked them to meet the needs of your students!