Possible cause is Slower rate of speech development. Action to take Your child's speech may be slower than her motor skills. If she is surrounded by talkative siblings or others in childcare, she may not feel the need to speak. Action to take Consult your pediatrician who will examine the child and test his hearing. Consultation with another specialist may be advised.
Possible cause is Normal period of nonfluency.
Action to take Your child is learning to coordinate his thoughts with his motor skills. Speak clearly and read to your child. Don't overcorrect him or finish his sentences. This stage usually passes quickly. Possible cause is Normal development.