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Bilingual Baby: Can You Decipher Languages At Only 6 Months Old?

Can a bilingual baby understand in which language a person is speaking even before they can speak? How old does a baby have to be before it can decipher which language is being spoken… or even realize there is a difference? And even more impressively, how do they do it?

bilingual baby

My bilingual baby in his second home… Mexico!

The way the brain of a bilingual baby works during language development is truly incredible! It utilizes patterns of pitch and sound, specifically the duration of the sound, to group together the words from different language systems. This grouping allows the bilingual baby to start to identify not only which system is being used, but which person generally uses which system. For this reason, bilingual children are generally very good at using the correct language system when addressing various people in a multilingual environment.

According to livescience, babies can actually learn the differences between languages as early as seven months old. The experiment outlined below actually made up a language of 11 words and then spoke that language to the babies while varying pitch and sound duration for each respective group. Both groups perceived the made-up language as a different language than that of their native, or first, language. The babies in the study were bilingual English/other from birth.

I have noticed this in my own son’s language development. You can see that he understands the differences between English and Spanish in our home. My wife and I almost always, as in 99.9% of the time, speak to him in Spanish. If for some reason one of us says something to him in English, he will react with a surprised look as if to say, “Papa, de que hablas?” It’s interesting to know that underneath all of that cuteness there is a little language-making machine spinning its proverbial wheels. This little bilingual baby certainly has his work cut out for him making sense of it all.

As parents of a bilingual baby, this research is important to us for two reasons:

The first reason is that it reinforces the necessity to be consistent when choosing one of the parenting techniques for bilingual children. As early as age six to seven months, your bilingual baby already knows the difference between the various languages that he is hearing. If you are constantly switching back and forth when addressing him, this may, on some level, cause confusion. Learning to speak as a baby is probably complicated enough without us clumsy adults confusing them!

The second reason is that it reinforces the importance of beginning to speak to the child in their second language as early as possible. If a bilingual baby can understand the differences between the two languages this early, they must then be learning aspects of the two languages as well. Studies have shown that a bilingual baby can begin to distinguish between his or her two languages as early as four months old; even if the two languages are in the same rhythm class.

In addition to picking up on sound and speech patterns, babies may be learning whole words as early as six months!

In another article on livescience.com, recent research has shown that babies respond to complete words by looking at the appropriate picture representing that word in front of them. For example, if you say ‘la leche’ the bilingual baby, assuming they know Spanish obviously, will look at a picture of the milk more often than he will of other pictures presented to him.

“I think this study presents a great message to parents: You can talk to your babies, and they’re going to understand a bit of what you’re saying,” Swingley said.

Whether your bilingual baby understands every word you say, or just gazes at you lovingly because you are their mother or father, great reasons still exist to chat it up with your baby. Especially you fathers! Fathers play a huge role in language development in children!

What do you think? Does your bilingual baby have this ‘ability’ to distinguish between his or her languages? Have you seen this elsewhere? Comment below!

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About Jeffrey Nelson

Jeffrey Nelson is a husband, father, author and bilingual living and working in the Midwestern United States. He lives with his Mexican wife and their son, Liam, who is currently being raised bilingual in English and Spanish.

6 comments… add one

  1. Gma Nelson

    I loved this article – so little Liam knows Gpa and I are talking a different language. Can’t wait to chat with him and hear English out of his cute little mouth too!

    1. livingbilingual

      Grandma’s are so proud of their little guys… thanks for the support! Hopefully others loved it as well… we’ll see if it generates any more comments :)


  2. Cecy Fencer

    I spoke Spanish to all my kids since I was expecting them. When my eldest was 3 and my second baby was 1 we started to live with my (English speaking) in-laws, the Spanish acquisition slowed down, but today my kid’s brains are bilingual. I still speak to them in Spanish most of the time, but the other 3 adults speak mainly English. The children understand Spanish (almost everything), they can read in Spanish, they can write in Spanish but they are afraid to speak it. I guess at this point immersion is a must.

    1. livingbilingual

      As I said in my post, that is apparently a really common thing. I have had conversations with teenage children whose parents speak almost no English and they tell me, in English, they are way more comfortable speaking English than Spanish. It’s kind of sad! Our brains are a little too good at deciphering and putting importance on necessary skills… they tend to think the community language is more important than the secondary language! Cheaters :)

  3. Marien

    Hola! Great article, thanks! We live in an English speaking community, Spanish is my first language and we are doing OPOL. I only ever spoken Spanish to my sons (age almost 5 years old, 3 years old and 15 months), my 2 oldest are bilingual and only speak Spanish to me (that’s our special rule). I just want to encourage other families that YES it is possible at least in our experience so far. I make sure we have plenty of opportunities to share time with other Spanish speaking families, I started a Spanish playgroup when my oldest was 4 months old, we have made great friendships through that group. I’m now homeschooling my oldest and I’m teaching him in Spanish only as this is the way we have always communicated, I feel that learning how to write and read is just an extension of talking. He gets enough input in English from daddy (who also understands and can speak intermediate level of Spanish) and of course from the community. English is not prohibit in our homeschooling (as reading levels when we go to the supermarket or when he wants to know what a signs says) but the interactions are always in Spanish. I would love to connect with other families that are in a similar situation than us. The gift of bilingualism is something we can’t deprive our children from, it’s hard work as parents but it’s so worth it and I know they will be grateful in the future. Don’t give up!

    1. Jeffrey Nelson


      Thanks for the great comment! I love all the Spanish input you are giving your children. I’m sure it’s turning out very well for you. It is most definitely possible and fantastic that you are living that out. We appreciate the encouragement. Your idea about a Spanish playgroup is fantastic as well… it’s important for the kiddos to integrate with others that speak the minority language.

      It’s also great that he’s getting good input from his dad and the homeschooling… which is fantastic in it’s own right. It sounds like you really have it together. Thanks for sharing with us!


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