Sibling Order and Language Development

How birth order effects a child

When a child is late to talk, most parents are quick to attribute the speech delay to the birth order. Others blame themselves, often stating that they didn’t give as much attention to the young child as they did to the older child.

“She is a little late to talk because her brother talks for her.”

“She hasn’t learned enough words to communicate because she doesn’t get a chance to say anything at home. Her siblings do all the talking.”

Do these statements ring a bell? 

But is it true that birth order influences speech development?

How Does Sibling Order Impact A Child's Speech, Language, and Social Development?​

The debate on the impact of birth order on language development seems to produce mixed results. For example, research published by Hanen Center found no evidence of language delays in later-born children compared to firstborns. On the contrary, a 2019 study found that the number of older siblings a child has negatively affects their verbal skills, including language development, verbal intelligence, and educational attainment. The researchers use the Resource Dilution Model that attributes the speech and language development problem to a family’s resources and their distribution among siblings.

For example, a child in a one-child family receives all the resources, including material things such as books and games, and personal resources such as attention and teaching. However, as the number of children increases, these resources are distributed among siblings meaning that the more children, the fewer resources are allocated per child. These arguments are further cited in another 2021 research using the same resource dilution theory to compare only-child to later-born, finding that the competition for resources and caregiver attention affects development.

Researchers Rufan Luo, Lulu Song, and I-Ming Chiu found evidence of firstborn advantage in early cognitive development and literacy skills. According to their research, at 0-3 years, firstborns outperform later-born children in cognitive assessments. In addition, the scholars stated that firstborn preschoolers have better reading skills, non-word and sentence repetition, and word reasoning skills, as well as vocabulary and grammatical skills and vocabulary growth rate during toddlerhood.

Do these differences mean that sibling order leads to language and speech delays?

First, I acknowledge that later-born children have different language experiences than firstborn children, which may influence the rate at which they attain certain milestones. 

But does this equate to language and speech delays? 

While the answer to this question may not be straightforward, research says it doesn’t. On the contrary, parents should interpret these differences from milestone perspectives. For example, firstborn children are said to achieve the 50-word milestone a month earlier than their second-born siblings. However, the younger siblings catch up faster, as the study shows no significant differences after the 100-word milestone. 

Therefore, if your younger child is experiencing some language problem, it doesn’t mean they are destined for a language delay. Yes, their language skills are developing differently compared to their older siblings, but that does not necessarily mean they will fall behind just because they are the youngest.

Besides, children develop language skills differently. For example, in some families, second-born siblings develop language skills faster than firstborn children. Thus, being the younger child does not necessarily put your child at risk of speech delays, just like being the oldest does not mean your firstborn will have superior language skills.

Below are some aspects that show second-born children develop some skills faster than firstborns.

Later-born children use pronouns earlier than firstborn children

Triadic (mother-child-child) interactions involving the mother and older siblings result in the advanced use of personal pronouns among later-born children than firstborns. This difference occurs because the home learning environment influences a child’s language and speech development. For example, older siblings improve a younger child’s ability to join conversations as they tend to adjust their language teaching strategies to their younger siblings. 

In addition, these children learn from overhearing speech from older siblings and adults, which becomes an essential resource for the child to learn. In this case, your younger child can listen and mimic your speech when speaking to another adult or with the older sibling. This helps them develop their language, social, and speech skills and learn to use pronouns such as me-you, he-she, and they-them at a younger age.

Later-born children have more advanced conversational skills

While firstborn children may be advantaged in developing grammatical and vocabulary skills, later-born children have better conversational skills. Tyler Christine McFayden explains that with firstborns, mothers often tend to teach meta-linguistic skills by correcting the child’s language use and tenses. However, with later-born children, language use is usually centered on activities and social exchanges.

Besides, later-born children are more exposed to multi-party conversations at home between parents and siblings. These conversations motivate them to learn and use the necessary social skills to be part of the conversations, exposing them to more mature language models and faster language development. 

These different perspectives show that younger and older siblings have different developmental patterns and experiences. However, none is better or worse than the other. Instead of thinking your child is experiencing delayed language, speech, or social development, focus on the different experiences and milestone achievements. 

For example, if you have an older firstborn with already developed language skills, your second-born is more likely to develop conversational skills faster. However, suppose your later-born child is growing up with more limited resources than your firstborn, including caregiver’ attention, books, and games. In that case, they are more likely to develop vocabulary and grammar slowly than your firstborn. These instances indicate that multiple factors influence a child’s language development, including the home learning environment, caregivers’ attention, older siblings’ literacy levels, and engagement in conversation. 

Instead of comparing your siblings, focus on milestones!

I know it is hard not to compare your children’s developmental patterns, but try harder to avoid the sibling comparison trap! As the family size increases with more children, your parenting style and experiences with each child will change, and that is okay. 

Just remember that every child is different; give them the space and support to develop at their own pace. I encourage you to look at your child as an individual and avoid comparing them with your other children. Instead, look at the milestones or developmental steps your child has achieved at a certain age.

If you are looking for a way to help your child’s speech and language skills progress, explore our services and check out our online course.


  1. McFayden, T. C. (2021). The Impact of Birth Order on Language Development in Children with Autism Spectrum Disorder in Simplex Families,
  2. Keller, K., Troesch, L. M., & Grob, A. (2015). Firstborn siblings show better second-language skills than later-born siblings. Frontiers in Psychology6, 705.
  3. Lowry, L. (2012). The effect of birth order on emerging language​. The Hanen Center: Hanen Early Language Program.
  4. OshimaTakane, Y., Goodz, E., & Derevensky, J. L. (1996). Birth order effects on early language development: Do second-born children learn from overheard speech? Child development67(2), 621-634.
  5. Havron, N., Ramus, F., Heude, B., Forhan, A., Cristia, A., Peyre, H., & EDEN Mother-Child Cohort Study Group. (2019). The effect of older siblings on language development as a function of age difference and sex. Psychological Science30(9), 1333-1343.
  6. Luo, R., Song, L., & Chiu, I. (2022). A Closer Look at the Birth Order Effect on Early Cognitive and School Readiness Development in Diverse Contexts. Frontiers in Psychology, 2717.
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