Children on the spectrum can have trouble understanding what is said to them and around them. They can also have trouble with organizing language for an answer and saying it. With some children, it is easily noticeable. With others, it is harder to see, but there is still a hidden cost to the processing load. There are ways to make communication easier so that the child is more effortlessly connected to the people and activities around them.
Be direct.
The general communication style in our culture is designed to smooth things out and not hurt anyone's feelings or self-esteem. But your child needs you to say it directly, and in as few words as possible. If you don't like something, don't roll your eyes and make an indirect statement into space along the lines of, "Maybe one day you will understand that this is annoying." Just say, "I don't like this," or "I find it annoying when you do this, can you please stop." I can't promise that your child will stop, but they will have a real chance of understanding what you mean.
Go for the literal meaning.
If you ask a child on the spectrum for help by saying, "Give me a hand," they just might give you their sweet little hand to hold. I have seen this happen. If you ask them, "Do you want to help?" chances are you will get an honest "No" because your child interprets it literally as a question about personal preference rather than a request for help. Make your meaning crystal clear.
Give time to process.
Give your child time. If they don't answer immediately, don't repeat what you have said or start helping them. It can disrupt their train of thought, and they will have to start all over again. For many children, it is helpful to have time to consider the question, especially if they need to make a decision or a choice. Ask your child if they would like some time to think. Check in with them later to see if they have decided on an answer. More often than not, your child will forget that they are supposed to think about something. You could make it more time-specific, for example, "If it's ok with you, I will check in again at dinner." And before dinner, you could say, "Remember I have asked you to think about something? I will be checking in about it soon." If you keep checking in patiently, it will be worth it because your child will be able to come to a decision without feeling stressed out.
Check for Understanding.
Many children on the spectrum pretend that they understood what is said to them. In response to a question they don't understand, they will answer yes or no because they either do not know how to ask for clarification, or they are too embarrassed to admit that they did not understand. As a result, they might miss information or end up in activities or situations that are uncomfortable for them. Offering choices or visuals can help. Always check your child's understanding, "What are going to do when we get home?"
Go light on humor, sarcasm, irony, and teasing.
Children on the spectrum can easily misinterpret these and end up with hurt feelings. When you know a child, you find out what types of humor they enjoy, what types of humor they don't appreciate, and what they misinterpret. Make sure you know the child before using different forms of humor. If you do not know a child well, the default is not to use much humor or to ask caregivers about it.
Keep your emotions in check.
Children on the spectrum often feed off your emotions. If you are angry or upset, your child can become just as angry or as upset. Because children on the spectrum can be sensitive to other people's emotions, you might just raise your voice a little bit for your child to misperceive you as yelling at them. Next thing you know, you are arguing with each other, or your child is even more upset than they were in the first place, and your interaction goes downhill. If you notice that your child is picking up negative emotions from you, it's better to stop. You can either make an effort to stay neutral or take the time to out to calm down.
Don't use touch casually and unexpectedly.
Many people have a habit of touching children when talking to them. I have seen a biking instructor give a child a playful knock on their helmet... after which the child refused to ride the bike that day or come back for a lesson in the future. Many children on the spectrum have touch sensitivities. Don't touch them unless you know their preferences, which might include asking permission and using very specific types of touch.