Sunny Days Blog

Bilingualism: Myths and Facts


As a bilingual speech-language pathologist, I frequently meet bilingual families who are advised to speak only English in their households due to the dangers of bilingualism. This advice comes from doctors, teachers, physical therapists, occupational therapists, speech-language pathologists, and other related professionals. While these professionals are well-meaning in their advice, the advice is not backed by research. Sadly, because of this poor advice, many families abandon their home language, which causes children to lose a portion of themselves, their language, and their culture. The purpose of this blog post is to debunk myths about bilingualism that are perpetuated day after day.

The Unfounded Myths of Childhood Bilingualism:

  • Learning two languages causes delayed speech and language development.

  • Children with delayed speech and language skills should only learn English.
  • Individuals with developmental disabilities (e.g. autism, down syndrome) cannot become bilingual.

Although these myths couldn’t be further from the truth, they continue to be spread like wildfire. Why they continue to be spread is unclear, but it bears repeating that these myths are not in any way true or supported by evidence. So, you may be wondering, what is the truth? What does the research say about bilingualism?

The Research-Based Facts of Bilingualism:

  • Learning two languages does not lead to delays or confusion.
    • Genesee, Paradis, and Crago (2004) reported that children with exposure to two languages have the innate ability to learn both without negative implications for successful development of either language.
    • Bilingual children may have vocabularies that are smaller in each language compared to norms for those languages, however, their overall vocabulary knowledge (from both languages) will be equal to that of their monolingual peers (Hoff & Core, 2015).
    • Research shows that monolingual and bilingual children meet speech and language milestones at similar rates (Genesee, Paradis & Crago, 2004).
    • Switching back and forth between languages in a given phrase or sentence (AKA code switching/code mixing) is indicative of normal bilingual development and is not a sign of confusion. Additionally, code mixing may reflect the cultural norms of the child’s environment (Genesee, Paradis & Crago, 2004).
    • Bilingual infants can easily differentiate between their two languages (Bosch & Sebastian-Galles, 2001).
  • Parents and family members should speak their native language at home with their children regardless of whether or not their children are delayed.
    • Research has shown that strong language skills in a child’s first language (L1) can assist with development of the second language (L2) (Genesee, et al., 2004).
    • A 1992 study conducted by Perozzi and Sanchez looked at bilingual children with language delays and found that children learned prepositions and pronouns in English (L2) twice as fast if instruction was first provided in Spanish (L1) compared to children who only received English instruction.
  • All children, with and without disabilities, can become bilingual.
    • Researchers have investigated bilingualism in children with developmental disabilities, such as autism and down syndrome, and have found that learning more than one language will not harm these individuals. Instead, bilingualism will enhance their overall language and socialization skills and improve their interactions with their parents and families (Kremer-Sadlik, 2005; Bird, et al., 2005; Genesee, et al., 2004).


The key takeaways here are that:

1. Families should be encouraged to use their native language at home because it is advantageous to their children’s speech and language development, as well as their cultural and linguistic identity.

2. Learning more than one language does not cause confusion or delays. With this in mind, the next time you meet a bilingual family in your professional or personal life, make sure that you are educating them on the benefits of bilingualism rather than continuing to perpetuate myths that have been unfounded for decades. I promise you that those families and their children will benefit from your sound advice.



Bird, E. K., Cleave, P., Trudeau, N., Thordardottir, E., Sutton, A., & Thorpe, A. (2005). The language abilities of bilingual children with down syndrome. American Journal of Speech-Language Pathology, 14, 187-199.

Bosch L, & Sebastian-Galles N. (2001). Evidence of early language discrimination abilities in infants from bilingual environments. Infancy, 2, 29–49.

Genesee, F., Paradis, J., & Crago, M. B. (2004). Dual language development and disorders: A handbook on bilingualism and second language learning. Baltimore: Paul H. Brookes Publishing Co.
Hoff, E., & Core, C. (2015). What clinicians need to know about bilingual development. Seminars in Speech and Language, 36(2), 89–99.

Kremer-Sadlik, T. (2005). To be or not to be bilingual: Autistic children from multilingual families. Paper presented at the 2003 at the ISB4: Proceedings of the 4th International Symposium on Bilingualism. Retrieved from

Perozzi, J. A., & Sanchez, M. C. (1992). The effect of instruction in L1 on receptive acquisition of L2 for bilingual children with language delay. Language, Speech, and Hearing Services in Schools, 23(4), 348–352.

Photo by Ryan Wallace on Unsplash


Courtney Caruso, M.S., CCC-SLP

Courtney Caruso, M.S., CCC-SLP is a bilingual (English/Spanish) speech-language pathologist and the owner and founder of Liberty Speech Associates LLC, a speech therapy practice located in Hackettstown, NJ. She is also the co-author of the book From Meals to Milestones: 35 Delicious Dishes to Encourage Child Development. For more information about Courtney, visit her website at