This is a hard question to answer. Early communication skills have wide ranges of
what is considered "normal". It is true that all children develop at different rates.
You may have had one child that started talking sentences by their second birthday and then your other child is barely putting words together by that time. Or, your one year old is babbling, but another child at playgroup is using words. It's so hard to know if they are "on track".
The US Preventive Services Task Force [2006] states: "Speech and language delay affects 5 to 8% of preschool children, often persists into the school years, and may be associated with lowered school performance and psychosocial problems". Studies find that boys are more likely to be late talkers than girls. I can attest that the majority of the young children I work with tend to be boys-- though I do see some girls as well.
I hesitate to give blanket statements about this question without more information. However, there are some questions you can consider. These comes from the rearch of Paul (2008) that differentiate late talking and more serious communication impairments:
Is your child meeting developmental milestones? A search on google will bring up milestones by age (make sure you use a reliable source such as healthychildren.org and NOT what people post on facebook groups!)
Joint Attention: does your child share a common focus with you. For example, if you point to something will they look at it?
Receptive Language: Late talkers have normal understanding of language (vocabulary and concepts), but below average expression of these things.
Gestures: Does your child point, wave, clap, etc?
Pretend Play: Do you see appropriate use of toys? For example, 'cooking food' or 'racing cars' versus doing repetitive movments with the toys (example- only spinning the car's wheels).
Are you seeing repetitive movements? (i.e. rocking or flapping hands)
Unusual vocalizations
I am a HUGE advocate of early intervention. Knowledge is power and the more you know about your child's language, the better you can help them! I would encourage talking to your pediatrician about your concerns. In most states, there are free educational resources that parents can access. In Iowa, contact Grant Wood AEA. Sounds & Smiles is able to offer some unique options, such as therapy at your home (in the Cedar Rapids area) or virtual consulations in Iowa and North Dakota! Parents are THE best teachers for young children-- they are with you all the time! Sometimes, you just need someone to guide ways to encourage language development-- that's what I am here for!