Early intervention is the key to a child's communicative success.
Children with communication delays can be identified as early as 18 months of age because they are not meeting their developmental milestones. There is a range of accepted communication milestones, but there are certain stages of development for which each child should progress.
The following represents the typical stages of development:

At 18 months of age, your child should:
- respond to his or her name consistently
- say at least 10 familiar words
- produce four or more different sounds (ba, da, na, ma)
- imitate familiar sounds (such as car or animal sounds)
At 21 months of age, your child should:
- say 15 to 20 words
- hand you a toy or other object on request
- understand common directions (such as "sit down" or "come here")
At 24 months of age, your child should:
- follow directions involving prepositions ("put it on the table")
- recognize objects by function ("show me what you can ride")
- say a minimum of 50 words
- put two words together ("more milk" or "go mommy")
- produce six or more different sounds (pa, ba, da, na, ta, wa, ma)
- be understood approximately 60% of the time (speech clarity)
At 30 months of age, your child should:
- consistently use two-word sentences
- ask for assistance
- answer yes/no questions
- be understood approximately 75% of the time
- be adding 100 new words per month
- imitate words and phrases easily
At 3 years of age, your child should:
- follow two-step directions ("go get your shoes and get in the car")
- use three- to five-word sentences
- ask "how" and "why" questions
- be understood 90% of the time by all listeners
- say most sounds correctly (except s, th, r, l and blends)