Children who are easily over stimulated or become upset easily may need concepts introduced slowly through one, or at most two, senses at a time. Try different approaches and watch your child's reaction. The right approach is the one that works for the individual child. This can help you determine whether your child is understanding or just not listening. When trying to determine if a child understands a verbal direction watch your facial expression and eye gaze.
Children read a lot of meaning from an adult's face.
When trying to figure out if your child understands different words test them several times over a few days. At any one moment a child may be tired, feel uncooperative or be focused on something, resulting in the child tuning you out, not listening to what you have just said. Keep verbal instructions short and stress the key words. A child may not focus on what you are saying for several beats into your statement. This makes it more likely the child will really understand and be able to use the idea no matter who or how it is asked in the future.