Simultaneous bilingualism (or multilangualism) is when a child acquires two (or many) languages simultaneously, for example when they are raised by parents speaking more than one language.

Sequential is when the child acquires the second language(s) after having considerably learnt the first language, for example when the parental tongue is different than the main language of the community or education system.

I've heard that these two will result in different types of bilingual. How will they differ? Which one will become better speaker of the two languages, assuming both languages are acquired during the critical age?

  • 1
    In what context have you heard this claim? I'd suspect it's from a context similar to "If you learn a language later in life, you cannot ever reach the same fluency as a native speaker"? If so, then there are researchers who disagree with that stance, so I'd wager they'll disagree with the claim you mention also. Commented Sep 24, 2011 at 22:48
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    @JürgenA.Erhard I heard in in the context of language acquisition by children. It is different from the context you mentioned because in this case both languages are learnt before the critical age.
    – Louis Rhys
    Commented Sep 26, 2011 at 14:30

17 Answers 17


People that grow up with more than one language, can end up being fluent in each language, and have native-speaker competency, but there will still be a dominant language. This could arise from social stigma (e.g. avoiding speaking a language that is not a dominant language in the community), from lack of full community to engage in (e.g. speaking a parent's native language in a community where few, if any others, speak that language, also commonly referred to as heritage speakers) or from simple cognitive barriers. This barrier is usually associated with when the L2 is learned and how much the L2 is used, which leads to four main groups: early critical period-high proficiency, early critical period-low proficiency, late critical period-high proficiency, late critical period-low proficiency.

So even with a Simultaneous Bilingual, there will be sociolinguistic pressures that make one of the languages a dominant language. In this sense you can analyse the development of the bilingualism in much the same way as you would any second language acquisition. Unfortunately there is no guarantee that the Simultaneous Bilingual will have better cross-linguistic ability when compared to the Sequential Bilingual, as this is a function of many variables, but I would feel comfortable putting my money on betting that the Simultaneous Bilingual would have a higher probability of being a high proficiency user of the L2, simply because they have more time, and we can assume that the L2 is acquired before the critical period is over. Whereas the Sequential Bilingual might not begin learning the L2 until later in the critical period. And it is important to recognize that the critical period fades over time, and at different rates for each person, and that the early critical period is more valuable than later stages of the critical period.

But to answer your question more directly, there will be differences between the two bilinguals, but neither is a solid predictor of language competency. Which I can attest to from personal experience, where I learned German at a later age (7) than my brother (5), and I have a greater competency than he does. A good book I can recommend is the book Second Langauge Acquisition, which has a lot of good information on bilingualism.


Simultaneous and sequential bilinguals differ in regards to the time a second language was introduced, but it does not necessarily determine which language will become dominant. Assuming both languages are learned during the critical age, the dominant language will be determined not by when the language was introduced, but by where, and how often, the languages are used.

For example, a child that is born to Japanese and Spanish parents that will go on to attend school where Spanish is spoken, Spanish will become the dominant language. Most of the child's life will be conducted in Spanish outside the household. A child born to Japanese parents that is introduced to Spanish during the critical period, and then goes on to attend Spanish school, will also use Spanish as a dominant language.

An individual's dominance in a language is not determined by early exposure, but by the dominance of use. Only by ensuring an environment in which both languages are used equally would we truly see the difference between sequential and simultaneous bilinguals.

If there were any difference, perhaps the simultaneous bilingual would have a better grasp of concepts than the sequential bilingual, as a simultaneous bilingual would have had to learn every concept can be defined using more than one word at a critical age in cognitive development.


Assuming the existence of a critical period in life to learn a language that extends from early childhood to puberty and affects both the acquisition of the first language and the acquisition of the second language according to (Penfield and Roberts, 1959).

In my opinion both cases are examples of bilingualism and what changes is the form of acquisition.

  1. Regarding simultaneous bilingualism, it is known that at the beginning it tends to mix both languages and create initial confusion, but once fluidity is acquired in both, they can be used interchangeably, even changing from one to the other automatically. In this situation two things can happen depending on the exposure to the language:

    a) One of them can become dominant.

    b) Have an indifferent use of the two in different contexts, achieving a perfect bilingualism.

  2. On sequential bilingualism is the one that is learned after acquiring a mother tongue usually when you have to attend school, this language L2 becomes the main and dominant, for its academic use. The reverse situation can occur at home if the parents are not responsible for vehicular L1 since the linguistic structures may be more deficient.

In my experience, the two types of bilingualism have nuances depending on the family and the social context. Going further, I believe that the ability to understand, write, read and speak should be separated. Use of spoken language even within schools produces rejection in sequential bilinguals because they are considered (themselves) disadvantaged with respect to the simultaneous ones. This point would deserve a good analysis.


If we are to compare between a person who went through simultaneous bilingualism and another one who went through sequential bilingualism, we'd be better off starting with their main characteristics:

Simultaneous bilingualism refers to learning two languages at more or less the same time, which means that those children will have two separate speech perception systems.

Sequential bilingualism refers to children acquiring a second language in stages that'd go from home language use to a nonverbal period followed by a formulaic usage of L2 with a final product of successful language use.

Having all those facts in mind, we can clearly see that they differ in how and when they start using a second language clearly and effectively. A simultaneous bilingual will start at a very early age whereas the sequential bilingual at a later period in their lives.

This takes me to the second question here about who may be the better speaker of the two languages and to answer that, we must remember that from the sequential bilingualism perspective, they should be better at using both languages because they learned their mother tongue first and then, with that control of grammar structures and language in general, they proceeded to learning a second language, which gives them a clear advantage over simultaneous bilinguals.

However, one may argue that simultaneous bilingual children have a better use of both languages because they have been doing that from a very early age and that might be true, but it is a fact that people always tend to favor one language over any other one when they are bilingual or even trilingual, which would go in detriment of the other languages spoken by them, especially because when a child starts using a second language more than their first language, language loss will definitely take place.


Roy Major's thesis at Ohio State described his child's simultaneous acquisition of English (from father) and Portuguese (from mother), and he has since worked in the area of acquisition and foreign accent. His book Foreign Accent should have some interest for you (though I haven't read it).

  • Can you summarise some of what he says?
    – curiousdannii
    Commented Mar 6, 2018 at 12:29
  • @curiousdannii, I have only my recollection of some remarks from Roy's advisor at OSU, David Stampe, to go on. Following a typological proposal of Donegan and Stampe that characterizes languages as either "rising" or "falling", in his thesis Roy found that early on, the child did not distinguish between the accent systems of Portuguese and English, but acquired this distinction only later.
    – Greg Lee
    Commented Mar 6, 2018 at 14:29

I would say that both types are examples of bilingualism. The only differentiation is they way of acquisition. With simultaneous bilingualism kids tend to mix both languages at early ages. This is the way of acquisition by having one parent speaking a language and the other a second one. However once they become fluent in both, they are capable to use one or another depending on the context, as well as switching from one into another automatically. They´ll develop both languages at the same time and, depending on the exposure, one of them will become dominant if the speaking tongue for the daily life is more practice than the other one. However if the balance is appropriate and the use of both is equal within the different contexts, that would mean that the bilingualism would be perfectly achieved. I would say that this way of acquisition is very successful although at the beginning can create confusion and maybe push the kids into some silent periods.

The sequential bilingualism is the one learnt after acquiring a mother tongue. This way happens when kids move to a different country and they have to study and attend school in the L2. So this language is going to become the main and dominant one, because is the one in use daily (academically, with friends..). However, at home kids are going to continue speaking in the mother tongue. But if this family tongue is not extremely worked and taught, the lack of vocabulary or structures will start to become poor while the L2 will get power and dominance.

From my experiences in this cases of acquisition, the L2 language is going to finally become the strongest one. But I have to say both ways of acquisition (simultaneous or sequential) are effective if they are worked properly. The differentiation is going to be related with the context, the way the family promotes and stimulates languages and the time of exposure.


Stemming from my personal experience as a language learner and from working as a language teacher for many years, I agree that both Simultaneous bilingualism and Sequentialis lead to different types of bilingual. Beginning with Simultaneous bilingualism (or multilangualism), when growing up I was raised with Catalan and Spanish as the main languages both at home and in school. Now as an adult, I have no problem being able to speak, read and write in both languages and I also have no problem disassociating one with the other, although you can argue that they are both similar languages, they are still two languages with each having its own alphabet and accent rules. To follow, with Sequentialis being the topic in mind here, my wife grew up in a home where Spanish was the main and only language being spoken by her parents, however at school the main language was English. Now as an adult, my wife is able to speak English better than Spanish and the same goes with her being able to speak, read and write, she is better in English than in Spanish.

Therefore, these two examples lead me to believe that simultaneous bilingualism is a method that should be applied to children during the “critical age” if parents want their children to be able to grasp two different languages at the same level.


Regarding the discussion I think that the simultaneous bilingualism refers to a person that learns two languages or more at the same time. For example, I am Basque and in the Basque country we speak Spanish and Basque, so I learn in a simultaneous bilingualism way because I learn Basque and Spanish at the same moment. However, the sequential bilingualism refers to learn the second language but only when the first is learned. There are different type of bilingualism but only in the process because the result is the same they have learn two languages, so the difference consist on that. In my opinion, both options are valid and there are going to become better speaker in both types of bilingualism. I men I don't think that choosing one of the two types of bilingualism will make you a better speaker, there are different situation so I can't compare them


In my experience the better speaker is the simultaneous bilingualism. When the child acquires 2 languages simultaneously being raised by bilingual parents. I know there are many articles that support sequential but I think the greater advantage is simultaneous. I think one can be bilingual with sequential learning as well but I think that simultaneous bilingualism will allow more depth of knowledge. I think the child will have an easier time with the language coming more naturally and fluidly to mind than sequential. I also think that the use of slang and jokes come more easily to the simultaneous bilingual as opposed the sequential. I think the most important thing to remember is exposure. Even though both languages are acquired during the critical age is the exposure the same between simultaneous and sequential? In general the exposure amount would be greater through simultaneous as opposed to sequential.


I have read some articles about this different ways of acquisition, so I can say that simultaneous acquisition differs on the sequential in the way that the children starts to use one language more than the other, in this stage is where is define the dominate one. In the sequential acquisition it is important to ensure the first language at home because if the original or home language is replaced by a second language and all support for the first is withdrawn, some children can lose skills in their first language (this can result in negative consequences for a child both within their family and the community, and in their future language development). In conclusion I can say that both ways if are used correctly by the parents will make a great bilingual speaker, but nevertheless in my personal opinion I think that a child who is involved into a simultaneous acquisition will become faster in a better speaker of both languages.


I think you are right in your approach when you say that depending when you acquire the second language you will have different types of bilingual (simultaneous or sequential). Anyway, in the cases that you raise, we are talking about early bilingualism and in both cases the L2 should be learned before the end of the critical period of acquiring a language. So in both cases the child would achieve the competence of a native speaker in both languages.

If your concern refers to the future, the key will be the time and quality of exposure the child receives in each language. The community and environment of the child will play an important role; keep in mind that if you don’t speak your L1 the language proficiency can considerably decline.

So we can say that becoming a better speaker is not only conditioned by when the languages are acquired, but the exposure time we have in each of them.


In simultaneous bilingual children at first could mixes the languages while communication and even though they acquired the languages at the same time, there will be one of it they use the most, so that language become dominant and in most cases the language used in the community they currently live in will be the dominant one. Instead in sequential acquisition the previous knowledge of the first language will help to develop skills in the second acquisition, also because of the knowledge in the first language the child will past by a silent period that will overcome over the time.

In conclusion Children in both types of bilingualism past over the same acquisition process and face the same issues, As for the linguistic competence at the end they both are going to be proficient speakers in each language even though there will be a dominant language.


Both types of bilingualism have different nuances depending on the family, the context where we are and if the second language takes part of a minority.

I have had experience with both cases and if we talk about effectiveness both have it, although we must consider the aspects mentioned before. A family who uses a simultaneous or sequential bilingualism where children speak with parents in English and in the community in Spanish, for instance, they are always in contact with both languages. They are able to speak in English at school, they can watch English movies at the cinema or at home, but, what happened if the second language is a minority culture? Imagine that you live in a small city where the migrant rate is low and the second language you want to teach children is not known, do you think it would be as easily to teach as other languages?

I reckon that more than the type, simultaneous or sequential, is the rules and possibilities that you can have to teach both languages. The context plays a vital role where children decides not to speak their second language because nobody else use it, let it apart and make it its acquisition slower.


As I understand, you can be fluent in both languages no matter if you are a simultaneous bilingual or a sequential one. However, I am going to talk about how they differ from my own experience growing up as a sequential bilingual. I learned two languages in the following particular context: I was about 6 years old, which could still be considered the 'critical age', when I was introduced to a second language. My family used one language at home but a different language was used in other of my environments.

I recognise that I have higher competence in my L1 than in my L2. Even though I feel I have native speaker competence in both languages, I could say I am a better writer, feel more confident in the use of the grammar and vocabulary, and make fewer mistakes using my L1 than my L2. Furthermore, I also admit that, while I have acquired my L1 unconsciously, it has taken me more effort learning my L2. I don't remember mixing both languages or having problems switching from one language to another, but it is true that at that age I already had a strong language understanding in the L1, as well as an advanced cognitive development in comparison to earlier ages. As I remember, the balance using both languages was settled to me when I was about 9 years old. Over the years, my L1 keeps being the dominant language. Sometimes I feel the development of my L2 is still in progress, not to say of my L3 which I started acquiring years later.

In summary, my experience leads me to believe that using simultaneous bilingual strategies in early childhood settings helps people to have higher probabilities in mastering proficiency levels in both languages, due to being early exposed to a multiple first languages development. Research shows that bilingualism is not associated with language delays so, the way we acquire a second language doesn't increase or decrease the chances of it. In terms of promoting cross-cultural understanding, I would say that both ways of acquisition, simultaneous and sequential, are very powerful. Likewise, I also share the opinion that context, the age of the child, the child's motivation, sociocultural factors, the values that are given to the different languages, length of time exposed to L2, and quality of exposure, among other factors, are fundamental aspects that affect the different ways of acquiring a second language. Thus, taken into consideration individual characteristics makes very difficult to elaborate further generalizations. Nevertheless, simultaneous acquisition and sequential acquisition are both valid ways to acquire more than one language in early childhood.


The question is too vague to effectively answer. When you ask, “How will they differ?” – are you wanting to know whether there will be a noticeable accent difference or a thought-pattern difference (e.g. it’s easier to ‘think’ in either language)? Unfortunately, sequential vs simultaneous bilingualism simply addresses the circumstances of acquiring the languages, not to the end result. So resulting speech and thought patterns will be extremely dependent on the individual and their linguistic context. When you ask “Who will be a better speaker?”- are you asking who will have a broader lexicon or better listening skills or stronger translating skills? The answer is likely “whichever receives a more thorough education, all other factors being equal.”

Language development is highly individualized, extremely context-driven, and of course education dependent. These cast an entire spectrum of nuance into any aspect of discussion. For example, it’s difficult to cast ‘simultaneous bilingual’ learners into the same light as many of them will still have ‘dominant bilingualism’ rather than ‘balanced bilingualism.’ For many of them, their language learning process may still have similar aspects to the sequential bilingual learner as their proficient language may help frame and inform the less proficient one.


In my experience working in a bilingual school and high school, parents always see as a positive thing that children learn languages giving them an advantage over other children and enriching them culturally and academically.

However, the myths about bilingualism have always existed, fed by professionals without support, feeding these rumors without solid evidence.

On the other hand, when trying to acquire a language it is normal to make mistakes without matter the individual is monolingual or bilingual. It is part of the learning that we all go through until the proficiency in the language will be acquired.

For example, in my school, it is normal to see how foreign children adapt quickly to the local culture and how they speak almost perfect Spanish in less than 6 months.


In December, 2019, a report was being made in my school district; the Oregon Department of Education allegedly wanted to know: "What language was my primary language?"

I wrote the following answer:

"I was born in Mexico, and learned Spanish as my primary language in my earliest years. I entered first grade, in the U.S., without knowing much English; elementary grade instruction in English was way over my head and unintelligible to my Spanish-trained brain."

"I had dual (U.S.A. / Mexican) citizenship because my dad was a U.S. citizen, (he was born in Los Angeles, California).

I was also simultaneously exposed to English in my later years as a child, as I learned to speak to my dad & my brother in English. With my mom, I spoke in Spanish."

"ODE language experts should know, & be familiar with, the term called "simultaneous bilingual", which best describes my upbringing, in terms of my linguistic development as a child."

After reading your entries in the discussion above, I conclude that I was both a simultaneous & a sequential bilingual. Simultaneous, because my dad spoke English to me as a child, and vice-versa, but also sequential because by 6 or 7 years of age, I was not conversant in English, and the public schools compelled me to learn English. Yet in those formative early years, 7 - 10, I had only learned conversational Spanish, while at school I was learning grammar, writing, reading, etc.

Which goes to show that definitional terminology, even in linguistics, is sometimes like throwing labels at people, which only give a partial understanding of the complex realities in which people develop and grow.

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