The innateness hypothesis proposes that humans are born with some innate knowledge of language. Hilary Putnam coined the term to describe Noam Chomsky's theory of Universal Grammar, which suggests humans possess an innate Language Acquisition Device containing the core principles of grammar. Evidence for innateness comes from observations that language acquisition in children follows predictable stages and is not dependent on formal teaching, and adults generally fail to achieve native-like proficiency in a second language. The critical period hypothesis of Eric Lenneberge further suggests there is an optimal period in early childhood for acquiring full native language competence.

1. Innateness hypothesis
Psycholinguistics
Level-6

2. Definition
• The innateness hypothesis refers to a linguistic theory of language
acquisition which holds that at least some knowledge about ‘language
exists in humans at birth’.
• This term innateness hypothesis was coined by Hilary Putnam.
• Putnam used the expression "the innateness hypothesis" to target
linguistic nativism and specifically the views of Noam Chomsky.

3. Putnam v/s Chomsky
• Putnam supported Chomsky's theory of “Universal Grammar” in
“innateness hypothesis”. This hypothesis targets the facts about
the complexity of human language systems,
the universality of language acquisition,
the facility that children demonstrate in acquiring these systems, and
the comparative performance of adults in attempting the same task.

4. Linguistic nativism
• Linguistic nativism is the theory that humans are born with some
knowledge of language.
• One acquires a language not entirely through learning.
• Human language is complicated and is said to form one of the most
complex areas of human cognition. However, despite its complexity,
children are able to accurately acquire a language within a short
period of time.
• Moreover, research has shown that language acquisition among
children (including the blind and the deaf) occurs in ordered
developmental stages.
• This highlights the possibility of humans having an innate language
acquisition ability.

5. • Chomsky's view that the human faculty of language is innate is also
affirmed by Steven Pinker. Moreover, Pinker, in his work ‘The
Language Instinct’, argued that language in humans is a biological
adaptation—language is hard-wired into our minds by evolution.
• Furthermore, in contrast to children's ease in language acquisition,
having passed the critical age for language acquisition the complexity
of a language often makes it challenging for adult learners to pick up a
second language.
• More often than not, unlike children, adults are unable to acquire
native-like proficiency.
• Hence, with this idea in mind, nativists advocate that the
fundamentals of language and grammar are innate rather than
acquired through learning.

6. Language acquisition device (LAD)
• In his work, Chomsky introduced the idea of a language acquisition
device (LAD) to account for the competence of humans in acquiring a
language.
• According to Chomsky, humans are born with a set of language
learning tools referred to as the LAD. The LAD is an abstract part of
the human mind which houses the ability for humans to acquire and
produce language.
• Chomsky expressed that children are able to derive rules of a
language through hypothesis testing because they are equipped with
a LAD.
• The LAD then transforms these rules into basic grammar.
• Hence, according to Chomsky, the LAD explains why children seem to
have the innate ability to acquire a language and accounts for why no
explicit teaching is required for a child to acquire a language.

7. Universal Grammar
• In his argument for the existence of a LAD, Chomsky proposed that for
a child to acquire a language, sufficient innate language-specific
knowledge is needed. These constraints were later termed as universal
grammar (UG).
• In universal grammar theory Chomsky suggested that all humans have
a set of limited rules for grammar that are universal to all natural
human languages.
• These rules are genetically wired into our brains and they can be
altered in correspondence to the language children are exposed to.
• In other words, under this theory, language acquisition is seen as a
process of filtering through the set of possible grammatical structures
in natural languages pre-programmed in one's mind and this is guided
by the language input in one's environment.

8. Eric Lenneberge
• The claim that linguistic ability is innate in humans is supported by the work
of the biologist Eric Lenneberge.
• He studied animal behavior and developed a list of characteristics that are
typical of innately determined behaviors. Such behaviors will be present in all
normal individuals of a species, whereas learned behavior will not be.
• For example, walking is a behavior for which humans are genetically
predisposed, but playing the piano or riding a bicycle must be specifically
learned. Here the question arises that, is talking like walking, or is it like
playing piano?
• To answer this, lets examine Lenneberge’s characteristics of biologically
controlled behaviors. If language acquisition has each of these
characteristics, we can safely assume that it is a genetically triggered
behavior.

9. Lenneberge’scharacteristicsof biologically
controlledbehaviors
1. The behavior emerges before it is necessary.
2. Its appearance is not the result of conscious decision.
3. Its emergence is not triggered by external events (though the
surrounding environment must be sufficiently “rich” for it to develop
adequately).
4. Direct teaching and intensive practice have relatively little effect.
5. There is a regular sequence of “milestone” as the behavior develops,
and these can usually be correlated with age and other aspects of
development.
6. There is likely to be a “critical period” for the acquisition of behavior.
(Lenneberge 1967)

10. Critical period hypothesis
• The critical period hypothesis by Linguist Eric Lenneberge states that
full native competence in acquiring a language can only be achieved
during an optimal period.
• This hypothesis supports the innateness hypothesis about the
biological innateness of linguistic competence.
• Lenneberge expressed that age plays a salient role in the ability to
acquire language. According to him, a child before the age of two will
not sufficiently acquire language, while development of full native
competence in a language must occur before the onset of puberty.
• This suggests that language is innate that occurs through development
instead of feedback from the environment.

11. • As a result, should a child not hear any language during this period,
the child would not be able to learn nor be able to speak. This
hypothesis is also said to explain why adults do not acquire languages
as well as children.
• Evidence for the critical period hypothesis can be seen in the case
of Genie and Isabelle where language was acquired outside of the
"critical period". This would lend support to Lenneberge's hypothesis.

12. Cases of Critical-age period
1- Genie was found in 1970 when she was nearly fourteen years old. She
had been abused and isolated since the age of twenty months. When
first discovered, Genie was completely silent. Thereafter her language
acquisition was extremely slow, and although she did learn to speak, her
speech was quite abnormal. She was able to memorize many vocabulary
items, but her expressions were formulaic and of a type such as what is
X and give me X.
2- Isabelle was discovered in 1937 at the age of six and a half. Her
mother, who was deaf and could not speak, had kept her isolated but
had not otherwise mistreated her. Isabelle then began lessons at Ohio
State University, and although her progress was at first slow, it soon
accelerated. In two years her intelligence and her language use were
completely normal for a child of her age.

13. Conclusion
• The linguistic abilities of these children suggest that humans can learn
language normally if they are exposed to a language by a certain age.
This evidence is corroborated by the evidence from second language
acquisition, which also indicates that there is a critical period appears
to extend from birth to approximately puberty.
• To conclude, children are apparently “preprogrammed” to learn
language. This innate linguistic ability enables children to analyze the
language of their environment and to create and refine their own
grammars until they can understand and produce their full range of
utterances that adults can produce.