My child is 1 1/2 years old, and he does not speak anything. Do I need to worry?

My firstborn does not speak at all until she is about 2 years old plus. I used to worry a lot about her and was advised to bring her for speech therapy. One day, out of the blue she speak in a full statement: "Ma Ma, give me milk milk" since then she has been speaking non-stop in a statement instead of words. Later, I found out some children are prefectionist like my girl, they dislike to make mistake and will only speak when they are confident. You can try read the resources provided by other mommies and start doing your own assessment. Need not to worry too much. My girl is 4 now and sonetime I wonder who is the Mommy as she can really talk and speak very well. Sonetime she even corrected me when I pronounced a word wrongly.