Let’s say that two or more babies/infants from the age of 0 were put in an environment without the affection of adults to teach them how to speak. Would the babies after 13 or so years develop their own language?

Let's assume that someone or something would take care of the babies, giving them food and water and so on, but never speak to them.

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    $\begingroup$ I forgot the details, but there was a case where a parent had locked their child in a room for years well into his teenage years. After the parents were discovered, and removed as unfit a study was conducted trying to teach him a language. I remember the study determined that if you don't learn a language by 13 you either won't be able to learn one or it will be incredibly difficult(nearly impossible). $\endgroup$
    – cybernard
    Commented Dec 21, 2017 at 22:11
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    $\begingroup$ @cybernard Are you thinking of Genie? That was a female child but her incredibly unfortunate abuse sounds like what you're thinking of. $\endgroup$ Commented Dec 21, 2017 at 22:43
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    $\begingroup$ There's a pretty tight critical period on language development that, if missed, makes it really tough to learn a language (fun fact! That's why some cultures have difficulty pronouncing sounds from other languages. If your language never used the sound, it's really hard to learn to make it once you're grown up!) $\endgroup$ Commented Dec 22, 2017 at 14:52
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    $\begingroup$ Here is a related question I asked a while ago: psychology.stackexchange.com/questions/10579/… $\endgroup$ Commented Dec 23, 2017 at 6:15
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    $\begingroup$ @cybernard A child in isolation is quite different from this question which focuses on two or more babies/infants developing a language among each other. $\endgroup$
    – Steven Jeuris
    Commented Dec 23, 2017 at 18:14

3 Answers 3


This question would require an experiment that cannot ethically be conducted, but it is interesting.

Wikipedia has an article on historical attempts at language deprivation experiments:

An experiment allegedly carried out by Holy Roman Emperor Frederick II in the 13th century saw young infants raised without human interaction in an attempt to determine if there was a natural language ... "foster-mothers and nurses to suckle and bathe and wash the children, but in no ways to prattle or speak with them ... But he laboured in vain, for the children could not live without clappings of the hands, and gestures, and gladness of countenance, and blandishments." ... James IV of Scotland was said to have sent two children to be raised by a mute woman isolated on the island of Inchkeith, to determine if language was learned or innate. The children were reported to have spoken good Hebrew ...

While these experiments had the advantage of a lax ethical environment, they also had a major disadvantage of poor methodology, and the accuracy of their documentation is very questionable.

There are quite a few documented cases of feral children, but none that I'm aware of who were raised together so as to have had an opportunity to develop language.

The most compelling case for the innateness of language development that I'm aware of is the Nicaraguan sign language (ISN):

... a sign language that was largely spontaneously developed by deaf children in a number of schools in western Nicaragua in the 1970s and 1980s. It is of particular interest to the linguists who study it, because it offers a unique opportunity to study what they believe to be the birth of a new language.

These children were in fact raised as normal children, but were language isolated, with no contact with other deaf children until school age. Some variables not well controlled for here include that they were exposed to the concept of language, were aware that other people communicated with each other, and already had a proto-language (mimicas). Nonetheless, they appeared to develop a proper structured language fairly quickly upon being introduced to each other, without any apparent support or encouragement from adults, who were entirely unfamiliar with any sign language.

There are similar examples of isolated sign-language development, such as ABSL and MVSL, but the problem with all of them is that the actual level of language isolation is not well controlled for, and hence not clear.

  • $\begingroup$ Thank you for your references and examples. I think the theme or setting could be an interesting topic in a novel though. $\endgroup$
    – John
    Commented Dec 21, 2017 at 20:11
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    $\begingroup$ @John It certainly could be. To add a generalization to Arnon's answer, it's currently believed that children raised in social deprivation have stunted linguistic capabilities for the rest of their lives; Genie, rescued at age 13, never gained full fluency in any language and nor (from what did we know) did Victor of Aveyron. What happens when babies are socially isolated from all but each other is less clear since there are no good examples, but without linguistic input one has to wonder. $\endgroup$ Commented Dec 22, 2017 at 0:24
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    $\begingroup$ Good video on this: youtube.com/watch?v=lCy3a3aUe8s $\endgroup$
    – Arnon Weinberg
    Commented Nov 22, 2020 at 19:34

While no cases of complete isolation of a group of children seem to exist, idioglossia (language invented and spoken by only one person or very few people) in twins is well documented and appears to be amplified by social isolation, as the sad cases of June and Jennifer Gibbons aka "Silent Twins" and the "San Diego twins" Poto and Cabengo illustrate. The effect appears to be bidirectional though, i.e. a sort of positive feedback effect is causing a cycle in which more isolation leads to more reliance on idioglossia which in turn fosters more isolation from the rest of society. (For the latter see Hayashi et al. for instance.)

Of course, in the case of twin idioglossia the children do not truly invent the very notion of language. Note however that the same can be said about child-developed sign languages like the Nicaguan Sign Language (NSL): adults still occasionally communicate with such children in a more primitive, ad-hoc sign language, and surely that happens before such children met each other in school etc., so the very idea of a sign language cannot be said to have been invented by these deaf children on their own, but they surely developed a much more sophisticated (and unique) sign language on their own. A qualitative difference between NSL and twin idioglossia is that in the NSL case the adults' (sign) language is more primitive. In this respect however, the parallel is not that different from the distinction between creole and pidgin. The latter is more primitive language of the parents, while the former is a more grammatically sophisticated version usually evolved by their children and later descendants.

In general, languages spoken by few people like twin languages and even those more widely spoken like Pirahã (and this includes sign languages of this kind like NSL) have one sure thing in common: there are bitter disagreements between linguists as to their features. The Wikipedia articles on Pirahã or document NSL those controversies well enough. For twin ideoglossic languages, while some researchers like Bakker have claimed high prevalence and gone to some lengths to describe their features, other researchers like Dodd and McEvoy have argued that such languages basically don't even exist (or if they do are extremely rare), being mostly phonological disorders that make them hard for us to comprehend, but that twins sharing the same genes share the same disorder, so they learn to undestand each other, while we can't do it that easliy.

So (insofar) not much in the way of firm conclusions can be inferred from these with respect to the development of languages that most people speak. And probably not that much can be inferred from them with respect to what would happen in a group of children in total isolation either...


Christine Kenneally asks a number of famous linguists this question and gives all their answers side by side at the end of her book "The first word" (2007). There's not really much consensus! Some say yes, some say no, and there's quite a bit of variety in the justification for each. Plus also some interesting intermediate answers that are something like "yes, but a linguist arriving on the island would immediately notice features of the language suggesting it had a short history".

This question is the last chapter for good reason, the rest of the book gives the context for why the answers are so varied.


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