Is There a Delay in the Development of the Child?

Our daughter is 18 months old. When should we be alert to go to the doctor immediately to check whether there is a developmental delay?

Child development experts state that signs of developmental delay can be detected when:

1. No smiles, happy expressions or interest in other people when the baby is 6 months or older.
2. No sounds, smiles, happy facial expressions in other people by 9 months or older.
3. No babbling at 12 months.
4. No reciprocal activities such as pointing, showing, reaching, or waving by 12 months.
5. Doesn't speak words by 16 months.
6. Does not say two or more words that have meaning by 24 months.
7. Loss of the ability to babble or interact socially with others, at any age.