Throwback (2014): English language development of toddlers from bilingual homes: What do older siblings have to do with it?

Those of us who have worked in early intervention with multilingual families know that the level of proficiency that young kids have in each language varies greatly. Although the factors that create this variability are less clear, one thing we do know is that amount of linguistic input has a strong relationship with how quickly young children develop proficiency in each of the languages that are spoken in the home (e.g., David & Wei, 2008; De Houwer, 2009; Gathercole & Hoff, 2007). To extend our understanding of the factors that create linguistic variability from child-to-child, the authors of this study looked at specific sources and contexts of input that might result in more robust language learning.

So, let’s first talk about input for just a minute before I go on to tell you more about this study. Anecdotally, it would be logical to assume that the adult who interacts with an infant or toddler on a daily basis (think: stay-at-home moms, stay-at-home dads, day care providers, nannies) provides the highest level of language input for that child, right? And, it would even be safe to assume that this would be the case for infants and toddlers who are learning English and another language (or, languages), am I right? This is exactly what I assumed before I read this article (And, there is research to back up this assumption, by the way. For example: Hoff-Ginsberg & Krueger, 1991). But, when Bridges and Hoff examined a different factor—influence of input from older siblings—and its relationship to young, multilingual children’s language learning, a different story emerged.

So, to back up for just a minute: why did they decide to specifically focus on older siblings? Well, the authors based their research on case studies of bilingual children (e.g., Caldas, 2006; Wang, 2008; Yip & Matthews, 2007) that suggested that because older siblings use English at school, they “[bring] English into the home” (p. 2). For instance, older, school-age siblings often provide a model of the dominant language (i.e., English) for the younger sibling, and prefer to use that language to interact with their younger brothers and sisters.


The authors carried out two experiments to determine the influence that older siblings might have on 16- to 30-month-old children’s language learning. The first study looked at whether having an older sibling would influence the level of exposure to and development of English in toddlers learning English and another language (such as Spanish, French, and Hebrew). The second study focused on both Spanish and English by looking at potential differences in the amount that both languages were spoken in homes with and without a school-aged sibling, and the impact that an older sibling might have on bilingual toddlers’ development of both languages.

So, what did they find? Well, the results definitely negated any of the assumptions that I had about sources of language input for the infant and toddler population! In general, the authors found that in multilingual families with school-aged children, younger siblings heard more English, their mothers spoke more English, and the toddlers had stronger English vocabulary and grammatical skills. (And, on the flip side, in the second study, the authors also found that toddlers without older siblings heard less English at home and were more proficient in Spanish.)

We spend a lot of time in our field focusing on training and utilizing parents as partners in therapy; particularly, when it comes to work with infants and toddlers in the home. (And, for good reason—it just makes sense, and there’s research to prove its effectiveness! In fact, we’ve reviewed some recent research that focuses on this here and here).

But, the results of this study seem to suggest that older, school-aged siblings may be an underutilized resource for SLPs working with young, bilingual children who are learning English. Given that they have the potential to provide the highest level of English input for infants and toddlers, maybe it’s time that we started thinking about training and utilizing older siblings, as we do with parents, when we work with infants and toddlers from multilingual homes.

*Note: The terms bilingual and multilingual were used interchangeably in this review to describe young children who are learning English and another language.


Bridges, K. & Hoff, E. (2014). Older sibling influences on the language environment and language development of toddlers in bilingual homes. Applied Psycholinguisticss, 35(2), 225–241.