You may want to explain that you and your child’s teachers believe that he is not learning as much as he can. Then, you could individualize the explanation by giving a simple example of his difficulty. You could point out that each child is unique and that everyone learns in a different way. Some learn by hearing; some learn by seeing; and some learn through their sense of touch. Explain to him that assessments will show how he learns best, so his teacher can help him learn more.