I can't converse with my child, or tell what they're saying, so I don't know their feelings or what they want to do.

Even when verbal exchange is hard, the child conveys a lot through expression, gaze, body movement, tone of voice, and behavior. First observe and record when they laugh, dislike something, or calm down, and "the child's own language" comes into view. For requests, showing two choices of real objects or photos to pick from makes it clearer. Picture cards, signs, and devices (AAC) also help convey "want to do" and "don't like." When you don't know, don't decide unilaterally—the stance of exploring together while watching their reactions matters.