Children who struggle in school often process language more slowly than other children. Many times parents and teachers ask a child a question and then make the mistake of not allowing them enough time to think and respond. All children (especially very young children) need more time to process what you say to them than adults do. There is some research to suggest that speaking at about the same rate as Mr. Rogers is the right speed for children. As they grow older, they can handle a faster rate, but many older children still benefit from a little extra processing time. See Teachers Should Talk Slower for a discussion of this.
Consider the impact of this in a normal conversation you might have with your child. How was school today? (No answer. Or, if given enough thinking time -- "Fine.") What did you do? (No answer. Or, if given time -- "Nothing.") Then we complain because our children won’t talk to us.
Speak more slowly than you think you need to speak. Then, ask open ended questions that cannot be answered with only one word. "What were two fun things you did today at school?" "What did you have to do today that you didn’t really like?" (Followed by, "Why did you not like that?") "Tell me about the learning center for today. What did you do?" These questions will spark memories for the day that your child will share using many words instead of just a few.
Give thinking time after you ask each question. When children are thinking, they are processing their own language in their head. If it takes them more time to process what you say to them, then it also takes more time for them to figure out the words to say to answer your questions. For some children this time is considerably more time than you expect.
Use the same strategy when disciplining your child. If your conversation is about something related to behaviors you want to correct, you need to use the same tactics. Parents tend to speak louder and faster when disciplining children. To the child who processes slowly they may not understand a word you say. This can be the reason why your child does not learn the lessons you want him to learn.
I have found it essential to slow down when I teach. It takes some practice, and you have to make sure another person who thinks more quickly does not answer for them. Try it with your child and let me know how it works!