Children learn differently and at different rates. Some kids need extra time learning to read, for example, especially if they're also learning a second language. On the other hand, some children might have trouble seeing, hearing, or speaking. Others may have a learning disability. If you think your child may have some kind of physical or learning problem, it is important to talk with your child's teacher, and perhaps to get expert help if needed.
If you are unsure where to start, read about some of the different reasons your child might be struggling. To learn more about reading difficulties, learning disabilities, and special education, take a look at the following articles from Colorín Colorado and other educational websites. This page is also available in Spanish.