Voice
Talking is not the only way
Some autistic people talk a lot. Some talk some of the time. Some do not talk with their mouth, and still understand everything.
A card, a keyboard, or an app can be your voice. Repeating a line you like can be an answer. Taking a long time is still answering.
You do not have to look at someone’s eyes to listen. Looking at the floor, a toy, or your hands is allowed.
Try this
Pick a hold-up card you might need. Practise showing it. You do not have to say extra words.