Bilingual language development: 5 questions parents often ask

In this blog I would like to address 5 questions that parents of bilingual children often ask:

  1. What influences bilingual language development?
  2. What are the advantages or disadvantages?
  3. When should children start learning languages?
  4. Which languages should we use and how?
  5. My child makes many mistakes when speaking. Should we be worried?

1. What factors influence bi- or multilingual language development?

External factors

  • From when the child learns one/more language(s).
  • How often the child hears the language(s)
  • Which languages the child hears
  • The quality of the language input
  • The status of the language (what meaning is given to a language)

The beginning of language learning was already discussed in the last blog. Of course, it makes a difference whether a child hears a language from birth or learns a language years later.

But even more important is how often a child hears a language. In what situations and in what environment does he or she hear and use a language? Closely related to this is the question of the quality of language input. I remember well when my father tried to speak English with our children. At some point we asked him to please stick to German 😊

Status also plays an important role. During my work in the social paediatric centre, I had families who thought it was better to give up their home language. They wanted to speak German so that the children would be better prepared for kindergarten or school. I will explain later why this is not necessary and why this can also lead to difficulties. So it may be that people themselves lower the status of a language. But it is also possible that society does not value people’s family language.

Internal factors

  • Cognitive abilities (e.g. memory skills, attention).
  • Language ability (one’s potential to learn languages)
  • Motivation

Cognitive functions

An important factor to consider is cognitive functions. Roughly speaking, these are all the processes in the brain that we need to think, acquire knowledge and perceive our world. If you want to know more about this, read the following blog. One important function that is mentioned again and again is short-term memory. In order to learn new words, we have to keep them in mind and link them to known knowledge. For example, we learn the Spanish word “flor”. We have to keep it in our memory until we have linked it to the German word “Blume” (flower). We memorise the form of the word. The word starts with /f/, has only one syllable. We associate characteristics with it such as “it is red, has green leaves.” Once these associations have taken place, the new word can be stored in long-term memory.

Language aptitude

Our linguistic talent, as we often call it, varies greatly. There are language talents, like my acquaintance, who speaks 6 languages fluently. My husband, too, was only asked in England which corner of England he came from. I, on the other hand, never got rid of my accent. Even children with speech disorders “caught” me right away and asked me which country I actually came from.

How well one learns languages depends on various abilities. In addition to memory skills, it is also important, for example, to be able to distinguish between different sounds. Recognising similar grammar structures is also important. If you would like to see examples of how language aptitude is tested, you can take a look at the tasks of the Modern Language Aptitude Test on this page.


Well, and motivation, I think is one of the most important factors. How many times I tried to teach my daughter the word ball when she was a baby because I thought it was easy, short and we often play with balls. I don’t know how many hundreds of times I told her… but a word like doll came quickly. There was an interesting article in the Guardian a while back about motivation in language learning, distinguishing between extrinsic and intrinsic motivation. An intrinsic desire may be that a child wants to better understand their Korean grandparents. An extrinsic reason may be that a young adult would like to study abroad but needs to know the language to do so. It is important to remember that motivation fluctuates and can change over time.

2. What are the advantages and disadvantages for children who grow up multilingual?

I’m sure many of you will quickly answer yes to this question. So, what exactly are the advantages? Three areas are important to mention here:

1. Social advantages:

Speaking many languages allows us to communicate with many more people without having to rely on a translator. This also allows us to build more contacts and learn about different cultures. There is less prejudice (see, among others, Castro et al., 2022). For example, I found it great to be able to communicate in English with people from all over the world. I learned that Maya the Bee also exists in Polish or which Spanish customs are common at New Year’s Eve and New Year’s Day. Well, eating 12 grapes at midnight was too tricky for me, so I dropped this custom quickly. With the knowledge you acquire in this way, you can also think about the world in a more differentiated way and adopt different points of view.

2. Linguistic advantages:

Especially when languages are similar, linguistic knowledge can be transferred from one language to another. This is especially true when learning new words (see e.g., Avila-Varela & Sebastian-Galles, 2021).

3. Cognitive advantages:

A big question that science is also working on intensively is the question of cognitive benefits. So, do thought processes develop better when people speak more languages? The data is not clear (see Giovannoli and colleagues 2020). It is complicated to design studies because multilingual subjects differ greatly.

Factors include:

  • how long a language has been learned
  • which languages are spoken
  • which tests are administered
  • how old the test persons were.

It is generally discussed that multilingual people have an advantage in the areas of selective attention and cognitive flexibility (e.g., Poutlin-Dubois et al., 2011). That the structure and function of the brain differed between monolingual and bilingual subjects was demonstrated, for example, by Grundy and colleagues in their 2020 study.

I think it’s definitely an advantage to speak several languages. I wish I had the superpower to understand all the languages in the world. However, that doesn’t mean that you should bombard children with multiple languages if there’s no reason for it. Nor does it help to put children in front of foreign language learning programmes, but more on that later….


The first thing to mention here is that multilingualism does not cause any language disorders! There is no evidence at all that speaking different languages has a negative effect on language development. Multilingual children also reach the known milestones. Delays may occur. Because the children do not get as much input from one language as their monolingual companions and also speak less of each language themselves, it sometimes takes longer to acquire a grammatical rule, for example. However, this is not a deficit!

A disadvantage worth mentioning is that multilingual children are more often misdiagnosed. Languages can overlap. Transfer effects occur (i.e. rules are transferred from one language to another). Therefore, language utterances more often appear to be incorrect. For example, my children mix the plural-s rule of English with plural rules of German, resulting in, for example, eine Mutter- viele Mütters. Also, their word order in German is often based on that of English (e.g., Ich bin froh, weil wir gehen in den Zoo).

In addition, not all languages are usually tested and the results are compared with monolingual children. How misleading this is can often be seen in the study of vocabulary. Some words are stored in one language, some in the other. But there are also words that are present in both. If one tests only one language, the vocabulary quickly appears reduced (Hoff et al., 2012). It is therefore important to test the entire vocabulary in order to obtain a representative assessment of vocabulary performance (see e.g. Thordardottir, 2011). Conversely, language disorders in multilingual children are more often overlooked because it is believed that the child has not yet sufficiently learned the surrounding language. Therapists often do not know the grammatical rules of the respective languages. Therefore, it is important that there is a close exchange between parents and the speech and language therapist.

3. When should children start learning different languages?

Again and again we hear the argument “the earlier, the better”. However, this must be seen in a more differentiated way. Yes, if children learn a language at an early age, they have more time to learn this language. And yes, some areas of language development develop early and early contact with language is important. One area, for example, is speech perception. It begins already in the womb. Children start early to pick up what they hear and to adapt their perception to the surrounding languages. Already during the second babbling phase, from about 6 months, children begin to focus on the sounds they hear. At the same time, their ability to differentiate sounds of other languages decreases (see Fox-Boyer & Schäfer, 2015).

But other areas of language development develop more quickly when children are a little older. This applies, for example, to the acquisition of grammatical structures and vocabulary. Older children are better able to put new words into context. They can be offered definitions and taught hierarchical references (e.g., “this is a motorbike. It belongs to the group of vehicles.”).

More important than the start of language learning is the amount of time children hear a language. Even if a baby already sees the Bulgarian grandma once a week. That will not be enough to establish the language. But if the grandma moves to the same town 3 years later and looks after the child for 4 hours a day, the child gets enough language input and can learn the language. Language quality is also important. Children need a language-rich environment, which can only be created if the interlocutors have a good command of the language and are “comfortable” with it.

In addition, children need people as conversation partners. We are social beings who react to our counterparts. Patricia Kuhl gave an exciting TED Talk many years ago. There she explained how language can only develop fully through interaction. So, you don’t need to spend expensive money on videos, online programmes or the like in the hope that your children will learn a language that way. Spanish lessons once a week may be fun and arouse curiosity about another language, but you should not hope for resounding success.

4. What languages should we use and how?

We just talked about how important the quantity and quality of language input is for children to learn languages. The best way to do this is to speak your home language(s). Using one’s home language has a number of advantages:

  1. The home language is usually the language close to one’s heart, the one in which we can best communicate, acquire and pass on knowledge. Our cultural heritage is also linked to it. Important holidays, religious festivals and customs are communicated through it.
  2. It allows parents to build deep parent-child relationships and have meaningful interactions.
  3. Using the home language also prevents children from gradually losing this language. If they no longer have contact and opportunities to speak it, language competence will decrease. As a result, the motivation and status of the language will also decline.

The amount of time your children hear each language will vary. That’s okay, it’s just important that none of the languages is neglected too much. As a rule of thumb, each language should have an equal share. This means that if there are two languages, the child should hear 50% of each language. Again, this is not to be followed exactly, but it gives a rough guideline.

Should we strictly separate the languages?

The belief that strict separation between languages is necessary to give children the best language role models persists. But as early as 2011, Paradis and colleagues stressed that there is little evidence that such a separation is the optimal way to raise children bilingually.

In some families, such a separation may make sense. For example, I have friends where the mother is from Germany, the father from Cyprus and they live in England. In their family, a separation makes sense and helps to give a reasonably even language input.

But strict separation is not necessary for your children to learn the languages. Nor does separation guarantee that your children will master all languages equally well (think of the internal and external factors that influence language learning).

Are you concerned that your child is not hearing enough of the surrounding language? Then think about what activities they can do to hear the surrounding language more. Maybe join a club, go to a dance group, go to a youth club….

Last but not least, it is not practical or realistic to always separate the languages. We experience many times a day that changing languages makes communication easier. The other day I had a conversation with my son’s teachers. Both are fluent in German and English. When I told them that we had to go to the Schuleingangsuntersuchung (i.e., school entrance examination), I didn’t look for definitions but said “Ragnar had to go to the school Schuleingangsuntersuchung ” and they all knew what was meant. This example brings up the next question:

Should a person mix languages?

So-called code switching is quite normal and has nothing to do with poor language skills. On the contrary, it is debated whether people who can switch between languages quickly have better executive functions. If you are not familiar with this term, you can learn more about executive functions here. It is also argued that you need to be good at languages to be able to make these switches.

Transfer effects, mentioned earlier in the blog, can also occur. Ragnar recently convoluted the words “ausbreiten” and “spread out” to “ausspreaden”.

And finally, a question on every parent’s mind:

5. My child shows many speech errors. Shall I be worried?

If you observe the following, I recommend you talk to your paediatrician:

  • Milestones are not being reached
  • There are clear problems in language acquisition compared to other children who are also growing up multilingual
  • There are many pronunciations errors
  • Language development seems to be “stuck“; no changes or improvements can be observed.

Multilingual children reach the same milestones as their monolingual peers. It is ok if they get there with some delay. But if milestones are not reached, one should take a closer look.

For example, children should be speaking around 50 words at 18 months. These can be words from all languages. This also includes onomatopoeias like (“woof”) or word forms that don’t really sound like the target word yet. For example, Ragnar said “babe” to the lamp. If your child speaks significantly fewer words, this may indicate a language development delay or disorder.

It is always important to compare performance with other multilingual children. Otherwise, there is a danger of believing too quickly that the child has a language delay or disorder.

Attention should also be paid to whether children are understood by others. Words spoken by four-year-olds should be 75% intelligible (Hustad et al., 2021). If strangers have problems understanding your child, this may indicate a speech disorder.

Each child develops individually. Sometimes it feels like the language explodes, other times it can take what feels like an eternity for children to acquire new language skills. My two are currently struggling with the dative and accusative in German (e.g., “Ich sehe der Ball”). No matter how often I give them corrective feedback, the errors persist.

In principle, I am always in favour of observing the children attentively. That way you can recognise early on if something is not going so well. Trust your gut feeling and seek help. Talk to your paediatrician and have it checked out by a speech and language therapist. If the professionals determine that the performance is age-appropriate, then you don’t need to worry. If there is cause for concern, you can intervene early and support the child appropriately.

One more important note: if there is a language disorder, it is not a reason to give up the family language (or one of the languages you speak). There is no scientific evidence that children with language disorders cannot learn several languages. Development may be slower. But exposure to multiple languages does not hinder language development.

Just as with monolingual children with language impairment, you should create a language-rich environment. Different ways should be used to communicate. The use of visual aids is very suitable. This could be gestures or pictures. If you would like more tips on how to support your child, check out my videos on Instagram or read my blog posts on Sprachtherapie Online.

The topic of multilingualism is extensive. I hope I have been able to gather and discuss the most important questions here. Whatever languages you speak in your family, celebrate their uniqueness, richness and embrace your diversity.

Lots of love and all the best,



Avila-Varela, D. S., & Sebastian-Galles, N. (2021). Study of labels phonological overlap across languages in bilingual toddlers. Poster presented at the 6th Lancaster International Conference on Infant and Early Child Development.

Castro, S., Bukowski, M., Lupiáñez, J., & Wodniecka, Z. (2022). Bilingualism is related to the expression of less stereotypes: The role of cognitive flexibility and motivation. DOI: 10.31234/

Fox-Boyer, A., & Schäfer, B. (2015). Die phonetisch-phonologische Entwicklung von Kleinkindern. In S. Sachse (Ed.), Handbuch Spracherwerb und Sprachentwicklungsstörungen – Kleinkindphase (pp. 39-62). München: Elsevier.

Giovannoli, J., Martella, D., Federico, F., Pirchio, S., & Casagrande, M. (2020). The Impact of Bilingualism on Executive Functions in Children and Adolescents: A Systematic Review Based on the PRISMA Method. Frontiers in Psychology, 11. doi:10.3389/fpsyg.2020.574789

Grundy, J. G., Anderson, J. A. E., & Bialystok, E. (2017). Neural correlates of cognitive processing in monolinguals and bilinguals. Annals of the New York Academy of Sciences, 1396(1), 183-201. doi:10.1111/nyas.13333

Hoff, E., Core, C., Place, S., Rumiche, R., Señor, M., & Parra, M. (2012). Dual language exposure and early bilingual development. Journal of Child Language, 39(1), 1-27.

Hofweber, J., Marinis, T., & Treffers-Daller, J. (2020). Experimentally Induced Language Modes and Regular Code-Switching Habits Boost Bilinguals’ Executive Performance: Evidence From a Within-Subject Paradigm. Frontiers in Psychology, 11, 542326. doi:10.3389/fpsyg.2020.542326

International Expert Panel on Multilingual Children’s Speech(2012). Multilingual children with speech sound disorders: Position paper. Bathurst, NSW, Australia: Research Institute for Professional Practice, Learning and Education (RIPPLE), Charles Sturt University. Retrieved from

Poulin-Dubois, D., Blaye, A., Coutya, J., & Bialystok, E. (2011). The effects of bilingualism on toddlers’ executive functioning. Journal of Experimental Child Psychology, 108(3), 567-579. doi:10.1016/j.jecp.2010.10.009

Thordardottir, E. (2011). The relationship between bilingual exposure and vocabulary development. International Journal of Bilingualism, 15(4), 426-445. doi:10.1177/1367006911403202

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