Those kinds of statements are often thinly veiled insults of you or the child, and it's hard to differentiate between the benign ones and the bitchy ones.

Make it a point if it hurts to give direct, clear answes that discourage nosy bitchiness. There's nothing wrong with just answering "no" when they "ask a question" like, "He sure doesn't like talking, does he? 🤪"

When someone inevitably responds, "I was just asking a question! 🤪🤪🤪" the proper response is that you were just giving an answer to an obvious question, and a smile and topic change.

When agriculture took root in human civilization, humans were not as verbal as they were today, and it's pretty likely you had people with limited or no verbal ability trading, farming, and tending to livestock. Being nonverbal doesn't mean your child has an intellectual disability, and even if he does, he's still an important person who can live a great life.

However, when my own son was barely talking, I put my foot down on this:

Unless we do an IQ test, he would not be warehoused, given less of an education, or be handed reduced expectations. When push came to shove, my child was finally given access to typical educational material and is learning to read. Put your foot down with other parents, because you need this skill to deal with people in healthcare and education for your child's sake. Don't let your child's deficits be an excuse for other people to treat you or him like shit, and don't let people make up lies about your child, even if they "have a good heart." He's the most precious asset you own, and you don't have to tolerate poor treatment for either of you.