Select your language

Suggested languages for you:
Log In Start studying!
StudySmarter - The all-in-one study app.
4.8 • +11k Ratings
More than 3 Million Downloads

All-in-one learning app

  • Flashcards
  • NotesNotes
  • ExplanationsExplanations
  • Study Planner
  • Textbook solutions
Start studying


Save Save
Print Print
Edit Edit
Sign up to use all features for free. Sign up now
Illustration You have already viewed an explanation Register now and access this and thousands of further explanations for free

Disclaimer/Trigger Warning: Some readers may be sensitive to some of the content in this article about Lenneberg. We want to make it clear this document serves an educational purpose and includes important information and relevant examples of Lenneberg's critical period hypothesis. Our team is diverse and we sought input from members in the writing of this article.

Who is Eric Lenneberg?

Eric Lenneberg was born in Germany in 1921, where he attended grammar school. Shortly after, he moved to Brazil with his family to flee Jewish persecution by the Nazis, and in 1945 he moved to the United States to study at the University of Chicago. After obtaining his bachelor's degree, he gained a PhD in Psychology and Linguistics from Harvard University. Lenneberg continued his education after this, going on to study neuroscience at Harvard Medical School.

Lenneberg's education prepared him for a future in academia, where he co-founded the field of biolinguistics alongside two other Harvard students, Noam Chomsky and Morris Halle. His first significant piece of work was published in 1964, entitled The Capacity of Language Acquisition (1964) . In it, he sets out his key arguments about the human biological capacity for language.

In 1967 he published what was to become one of his most influential books, Biological Foundations of Language (1967) ' . He demonstrated the importance of biological origins in linguistics and popularised the idea of a critical period for language acquisition. Lenneberg was interested in the relationship between biology and language development, and his goal was to develop a biological theory of language.

Lenneberg died in 1975. He pioneered ideas in the field of language acquisition and cognitive psychology.

Lenneberg's The Capacity of Language Acquisition (1964)

In his paper The Capacity of Language Acquisition (1964) ¹ , Lenneberg developed the concept of innateness in language acquisition . His ideas were picked up by other linguistics, such as Noam Chomsky and Steven Pinker.

Lenneberg criticised other social scientists, stating that they 'regard language as a wholly learned and cultural phenomenon'. He argued instead that:

... man (sic.) may be equipped with highly specialized, biological propensities that favor and, indeed, shape the development of speech in the child ... (p.579).

He also proposed the idea that although the capacity for language is innate , it has to be triggered by the environment. The innate capacity for language will not be realised in full if a suitable environment is not present.

Lenneberg presents four arguments to support his ideas:

  1. Variation within species.

He dispelled the idea of universal grammar, suggesting that the different phonological, grammatical and semantic systems in the languages of the world be recognised.

  1. History within species.

Lenneberg proposed that languages, like fashions, have histories. There is no historical record showing that there has ever been an absence of grammar:

We would not have to expect a gradual and selective process culminating in present-day languages. (p.588)

This supports his idea that the capacity for language is innate in all humans.

  1. Evidence for Inherited Predisposition.

Lenneberg says that

... all men (sic.) are endowed with an innate propensity for a type of behavior that develops automatically into language and that his propensity is so deeply ingrained that language-like behavior develops even under the most unfavorable conditions of peripheral and even central nervous impairment (p.589)

He goes on to give examples of how language is an inherited phenomenon. This idea was new, and stood in opposition to many linguists of his day, who theorised that language was a culturally learned phenomenon.

4. Presumption of specific organic correlates

He then develops the idea that speech develops automatically as long as a person grows up in a speech-rich environment:

The appearance of language may be thought to be due to an innately mapped-in program for behavior (p.600).

Lenneberg demonstrates that human organs are biologically predisposed for language acquisition.

The Biological Foundations of Language (1967)

Lenneberg's book 'Biological Foundations of Language' (1967) is considered to be a classic work in linguistics . In a recent tribute it was described as:

The scope and depth of Lenneberg's book is intimidating, even upon rereading 50 years after it was first published. (p.7)²

It's considered by many to be ahead of its time.¹ Let's summarise the book.

Through a use of theoretical data and clinical observations, the book aims to show the significance of the biological origins of language. The book was influenced by Lenneberg's peer, Noam Chomsky. Chomsky addressed aspects of the formal nature of language in the appendix of the book.

In the book, Lenneberg claims that:

biology has been badly neglected (p.7)

He intended to:

reinstate the concept of the biological basis of language capacities (p.8).

He developed this aim by seeing language as a mental 'organ', which develops the same way that other organs do. He wanted to show that the child's process of obtaining language displays similarities to general biological development.³

The book calls for a clear biological approach to the study of language. This had a profound impact on cognitive science at the time. He proposed new ideas on the topics of genes, development and maturation. Lenneberg argued that:

genetic mechanisms play a role in the development of an individual's behavior (p. 22).

He acknowledges the indirect relationship between genes and traits and rejected the idea of a special gene for language.

His work did raise important questions, prompting decades of further research.

Lenneberg's 'Critical Period Hypothesis'

The Critical Period Hypothesis was popularised by Lenneberg in the Biological Foundations of Language (1967). The hypothesis holds that there is a critical period for a person to learn a new language with native proficiency and that acquiring a new language after this critical window has closed is difficult. This period usually starts at around age two and ends around puberty.

Lenneberg based his arguments on research he conducted on the differences between adults and children and their ability to learn a language. He studied individuals with brain injuries and learned that children with brain injuries were more likely to recover and learn a language than adults who had similar brain injuries.

An example of a famous case study is Genie, a 'feral child'. Genie was a victim of abuse and isolation as a child, which impeded her ability to learn her first language. An attempt was made to develop her language skills, but with limited success. Although she made progress, she wasn't able to achieve full (ie. native) competence. The example of Genie is used to support Lenneberg's critical period hypothesis.

Lenneberg based his hypothesis on first language acquisition. However, it can also be applied to second language acquisition. It has been observed that when learning a second language, children generally develop their language to a higher level compared to adults.⁴ This can be attributed to children having a higher level of mental neuroplasticity compared to adults.

There are examples of adults who achieve native proficiency in a second language; but this is quite rare. In general, adults make mistakes in a second language, whether it's in their pronunciation or grammar. The inability to obtain good pronunciation has been explained by a loss of function in the neuromuscular system over time.

Opponents of the theory argue that other factors have a greater impact on a person's ability to learn a second language. These include the effort put in by the learner, the learning environment, and the time spent learning.

Lenneberg - Key takeaways

  • Lenneberg's work made him a major contributor to the field of biolinguistics.
  • Lenneberg believed that the capacity to acquire language was biologically innate.
  • Lenneberg proposed the 'critical period hypothesis' in his book Biological Foundations of Language (1967).
  • The case of Genie, a feral child, offered direct evidence in support of the critical period hypothesis.
  • Lenneberg disagreed with many of his contemporaries in the field of linguistics; he thought that the biological basis of language capacity was being understated.

1. Lenneberg, E. The capacity for language acquisition. In: The structure of language, ed, JA Fodor & JJ Katz. Prentice Hall, 1964.

2. Patrick C. Trettenbrein, 50 Years Later: A Tribute to Eric Lenneberg's Biological Foundations of Language, Biolinguistics, 2017.

3. C Boeckx, VM Longa, Lenneberg's Views on Language Development and Evolution and Their Relevance for Modern Biolinguistics, Biolinguistics, 2011.

4. Birdsong D., Second Language Acquisition and the Critical Period Hypothesis. Routledge, 1999.


Eric Lenneberg was a linguist and neurologist. He played an important role in the development of ideas on language acquisition and biolinguistics.

Lenneberg argued that the capacity to learn a language is innate, in opposition to contemporary linguists of his time. For a person’s full language capacity to be realised, they must grow up in an environment where language is spoken.

It is about the significance of the biological origin of language. The book offers a critical review of the common conceptions about language and details new ideas, and some evidence to support them.

Eric Lenneberg was born in Germany in 1921, then fled to Brazil to avoid Nazi persecution. He obtained his bachelor’s degree from the University of Chicago and soon after received a PhD in Psychology and Linguistics from Harvard University. He published the book Biological Foundations of Language in 1967. He died in 1975.

Final Lenneberg Quiz


What period of a person’s life is the critical period?

Show answer


From around 2 years old until puberty.

Show question


How are adolescents more capable of learning a new language than adults?

Show answer


The brain of adolescents has a higher level of neuroplasticity since they are still in the critical period.

Show question


What field of linguistics did Lenneberg play a major role in creating?

Show answer


Lenneberg played a major role in the development of the field of biolinguistics.

Show question


Where was the idea of the critical period first introduced?

Show answer


In the book ‘Biological Foundations of Language’ (1967) by Eric Lenneberg.

Show question


Why was Genie unable to develop native proficiency in her first language?

Show answer


She didn’t have the opportunity to develop basic language skills during the critical period.

Show question


True or False? Adults are unable to develop native proficiency in a second language.

Show answer


False. It is more difficult, but adults can still develop full proficiency in a second language.

Show question


True or False? Lenneberg believed language was developed through social means.

Show answer


False. Lenneberg believed that the capacity for language acquisition was innate in all humans and that the learning pathways were already there.

Show question


True or False? Lenneberg believed that a spoken language environment was needed to learn a language.

Show answer


True. Although he proposed that language acquisition was innate in all humans, he believed that the right environment was also necessary.

Show question


What factors determine how successful an adult is in learning a second language?

Show answer


The effort put in, the time spent learning, the learning environment and their age.

Show question


Why do adults who learn a second language often have a foreign accent?

Show answer


The neuromuscular system of adults is less adapted for change which affects their pronunciation of a new language.

Show question


of the users don't pass the Lenneberg quiz! Will you pass the quiz?

Start Quiz

Discover the right content for your subjects

No need to cheat if you have everything you need to succeed! Packed into one app!

Study Plan

Be perfectly prepared on time with an individual plan.


Test your knowledge with gamified quizzes.


Create and find flashcards in record time.


Create beautiful notes faster than ever before.

Study Sets

Have all your study materials in one place.


Upload unlimited documents and save them online.

Study Analytics

Identify your study strength and weaknesses.

Weekly Goals

Set individual study goals and earn points reaching them.

Smart Reminders

Stop procrastinating with our study reminders.


Earn points, unlock badges and level up while studying.

Magic Marker

Create flashcards in notes completely automatically.

Smart Formatting

Create the most beautiful study materials using our templates.

Sign up to highlight and take notes. It’s 100% free.