Do second and third-born children really talk late? The effect of birth order on language development

By Lauren Lowry
Hanen Certified Speech-Language Pathologist

“He’s a little late to talk because his older sister talks for him”.

This statement has been made by many parents with more than one child. But is it really the case that second and third children speak later than first-borns? And if parents do see a difference in the language development of their later-born children, should they be worried?

What the research says about birth order and early language development

Many people believe that later-born children don’t get the same amount of attention or one-to-one interactions that first-borns do, causing them to talk late.

Several studies have looked at the impact of birth order on language development. While they found some interesting differences between first and later-born children’s language development, later-born children are not delayed in their language development and first-borns do not have better language skills than their siblings. Even though mothers reported that their first-borns knew and understood more words than their later-born children, the research contradicted this.

The research did produce some interesting differences in first and later-born children’s early language skills:

  • First-born children reach the 50-word milestone earlier than later-born children. But later-born children catch up quickly and there are no lasting differences in vocabulary between the two siblings.[i]
  • The overall language development of second-born children was the same as their first-born siblings, but second born children were more advanced in their use of pronouns (eg. my, mine, you, your)[ii]
  • While first-born children were more advanced in vocabulary and grammar, later-born children were more advanced in their conversational skills[iii]  

Why do siblings have differences in early language skills?

The differences parents may see in the early language development of their first-born and second-born children may be influenced by the different language environments that each child is exposed to (by virtue of who is in the family and the kinds of interactions they have). For example, first-born children may benefit from more one-to-one attention from their parents. However, later-born children may benefit from a greater variety of conversations, such as overheard conversations between caregivers and other siblings.

This implies that overhearing and participating in conversations with older siblings helps a younger child develop language by providing a more varied and sophisticated model of conversation.

In summary, it seems that the different language environments first and second-born children are exposed to have an impact on the early language strengths each child develops. However, the research shows that differences between first- and second-borns disappear very quickly, and that a second-born child is no more likely to have a language delay than a first-born child. 

So how do you know if you should be worried?

What’s most important is not whether your second-born child speaks as early or uses as many words as your first-born child, but whether or not each child is meeting the appropriate language milestones for his or her age. It’s normal for your children develop language skills at slightly different rates, and you only need to worry if important milestones are not being met.

Click here to take a look at specific warning signs of language delay based on the age of your child. 

If you find that your child isn’t meeting these milestones, don’t assume that he’ll “grow out of it” because he’s a second or third-born child – consult a speech-language professional right away. The earlier he gets the extra help he needs, the greater his improvement will be!

For more information about the importance of getting help early when you’re worried about your child’s language development, click here.


Berkowitz, C. Pediatrics: A Primary Care Approach, page 55. Elsevier Health Sciences, 2000.

Berglund, E., Eriksson, M., Westerlund, M. (2005). Communicative skills in relation to gender, birth order, childcare and socioeconomic status in 18-month-old children. Scandinavian Journal of Psychology, 46, 6, 485-491.

Bornstein, M., Leach, D., and Haynes, O.M. (2004). Vocabulary competence in first- and second born siblings of the same chronological age. J. Child Lang. 31, 855–873.

Hoff, E. Language development, page 69. Cengage Learning, 2005.

Hoff-Ginsberg, E. (1998). The relation of birth order and socioeconomic status to children's language experience and language development. Applied Psycholinguistics19: 603-629.

Oshima-Takane, Y., Goodz, E., Derevensky, J. Birth Order Effects on Early Language Development: Do Secondborn Children Learn from Overheard Speech? Child Development. 67; 2: 621-634.

Reilly, S., Wake, M.,Bavin, E., Prior, M., Williams, J., Bretherton, L., Eadie, P., Barrett, Y., Ukoumunne, O. Predicting Language at 2 Years of Age: A Prospective Community Study. Pediatrics. 2007; 120: 1441-1449.

Robertson, Renee. Toddlers That Don’t Have Much to Say: A Look at Speech Delays Among Siblings. Preschoolers Today. Retrieved July 5, 2011

Tomblin, J. B. The effect of birth order on the occurrence of developmental language impairment. The British Journal of Disorders of Communication. 1990; 25(1):77-84.


[i] Berglund, Eriksson, and Westerlund, 2005

[ii] Oshima-Takane, Goodz & Derevensky, 199

[iii] Hoff-Ginsberg, 1998

For more than 35 years, The Hanen Centre has taken a leading role in the development of programs and resources for parents and professionals to help all preschool children develop the best possible language, social and literacy skills, including those children with or at risk of language delays and those with developmental challenges such as Autism Spectrum Disorder.