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

My child is currently 2 yrs old and only started more single words in recent weeks after some early intervention therapy. I agree that every child develops at different phase. Apart from speech delay, observe if your child has other developmental delays or behaviours that can cause worry. A single developmental delay is less worrying but if they are more signs, you may want to seek professional assessment and apply early intervention if required.