This is a link to a good piece about nonverbal communication (actually better termed nonspeaking communication): https://iancommunity.org/aic/neglected-end-autism-spectrum
There are a lot of means of communication besides speech. For example, a person’s posture, tone of voice, gestures, eye contact, and facial expressions are all commonly used alongside speech. However, these are normally overlooked. Many people consider them supplemental to the words used. Which is funny, because in my experience they’re sometimes even more important than the words a person uses. A simple change in expression or a particular tone of voice can change the whole meaning of a sentence.
But when it comes to autistic communication, the expectation is that words are the ultimate goal, and everything else should be ignored.
Perhaps you’re familiar with the above examples of nonverbal communication. Hopefully you recognize their importance. Something we don’t typically recognize, though, is that behavior is also communication.
Behavior as Communication
For example, refusing to do a thing is communicating something. It could be “I don’t like this thing.” Or it might be, “I am doing particularly poorly today, and rejecting this thing I normally enjoy should tell you this is important.”
The exact reason may be unclear, but the message needn’t be clear and precise to be a message.
The correct response to “challenging behavior” is not to punish the person. It’s to ask “why?” What might be happening with the person? Some example questions: Are they in pain (gastro-intestinal problems are common!)? Perhaps they’re frustrated because their communication isn’t being recognized or respected? Have you or they met all their needs? Are you presuming competence and intelligence when talking to them, or are you treating them like you would a small child?
It’s common, unfortunately, to treat nonspeaking people like small children. The presumption seems to be that since they don’t speak, they also don’t have the intelligence to speak. This is categorically false. The counter-examples are numerous. Off the top of my head, Naoki Higashida, the author of The Reason I Jump, is one. Another is D. J. Saverese, who starred in the movie Deej. Finally, there’s Owen Suskind, whose father wrote about him in Life, Animated. Each of these people struggled with typical speech despite being quite intelligent. Each found non-traditional ways to communicate.
Unfair Tests
Our intelligence-measurement tools typically limit us to only measuring people with near-fluent speech, which bars many nonspeaking autistic people from getting fair test results. For adults, there’s also the expectation that they can read. This isn’t always the case, and not even for the usual reasons. Autistic people sometimes also suffer learning disabilities, including dyslexia, tunnel reading, contrast or resolution impairment, and even environmental distortions. We might have 100% functional eyeballs, but the muscles that govern their movement might be uncoordinated. The words on the page might seem to flutter, wiggle, or shake rather than holding still the way they ought to.

A Lifetime of Growth
It is fashionable, in the world of autism therapy, to push for therapy (especially Applied Behavioral Analysis) as early as possible in the autistic person’s life. There’s this sort of loudly unstated assumption that if you don’t get a person speaking before a certain age (6, I guess?), they may never speak at all. Leaving aside the incredible amount of abuse that typically accompanies an ABA program… this article, and many others, show us how false this assumption is.
Psychology itself has progressed past this incredibly backwards mentality decades ago. While we once believed that you truly couldn’t teach an old dog new tricks, the reality is that dogs of any age can learn new tricks. And humans of any age can learn new things. The term for this ability to grow and change over time is “neuroplasticity.” Neuro, like neurons, the nerve cells in your brain. And plasticity, like plastic: moldable, changeable, and shapeable.
Autistic people are people. Like any person, we have the ability to grow and change. Being autistic doesn’t change that. Not speaking fluently doesn’t change that. Communicating with a Picture Exchange Communication System (PECS) doesn’t change that. Nonverbal communication is just as valid as fluent speech, and sometimes far more powerful.
The question has never been “when will my child speak fluently?” It has always been “am I listening to what they’re telling me?” Because all humans communicate. Whether that’s with fluent language, a text-to-speech app on a phone, or simply pointing and smiling is irrelevant. Are you listening?