Language Acquisition Device (LAD)

Language Acquisition Device: the Nativist Theory

The concept of Chomsky's LAD theory falls into a linguistic theory known as the nativist theory, or nativism. In terms of language acquisition, nativists believe that children are born with an innate ability to organise and comprehend the fundamental laws and structures of a language. Nativists believe this is why children can learn a native language so quickly.

Whilst behaviourist theorists (such as B. F Skinner) argue that children are born with minds that are 'blank slates' and learn a language by imitating their caregivers, nativist theorists argue that children are born with an inbuilt ability to learn a language.

In the nature vs nurture debate, which has been ongoing since 1869, nativist theorists are typically team nature.

For many years, behaviourist theorists were winning the language acquisition debate, mainly due to a lack of scientific evidence behind the nativist theory. However, all that changed with the arrival of Noam Chomsky. Chomsky is perhaps the most influential nativist theorist and helped revolutionise the field of linguistics in the 1950s and 60s by treating language as a uniquely human, biologically based, cognitive ability.

Language Acquisition Device: Noam Chomsky

Noam Chomsky (1928-present), an American linguist and cognitive scientist, is considered the pioneer of the nativist theory. In the 1950s, Chomsky rejected the behaviourist theory (which states that children learn a language by imitating adults) and, instead, suggested that children are 'hard-wired' to learn a language from birth. He came to this conclusion after he noticed that children were able to form syntactically correct sentences (e.g. subject + verb + object) despite receiving impoverished language input (baby talk), and not being taught how to do so.

In the 1960s, Chomsky went on to propose the concept of the language acquisition device (LAD for short), a hypothetical 'tool' that helps children learn a language. According to his theory, all human languages share a common structural basis, which children are biologically programmed to acquire. This hypothetical device in the brain enables children to understand and generate grammatically correct sentences based on the language input they receive. Chomsky's theory was a departure from behaviourist theories of language acquisition and has been influential in the field of linguistics, although it has also sparked considerable debate.

Language Acquisition Device meaning

Chomsky proposed the LAD theory to help explain how children are able to use the basic structures of language, even though they rarely receive instruction on how to speak their native language. He originally suggested that the LAD contained specific knowledge that is key to understanding the rules of language; however, he went on to adapt his theory and now suggests the LAD works more like a decoding mechanism.

Chomsky stated that the LAD is a uniquely human trait and cannot be found in animals, which helps explain why it is only humans that can communicate through language. Although some apes can communicate via signs and images, they are unable to grasp the complexities of grammar and syntax.

It's important to remember that the LAD is a hypothetical tool, and there is no physical language device in our brains!

Language Acquisition Device characteristics

So how exactly does the LAD work? Chomsky's theory proposed that the Language Acquisition Device is a biologically based hypothetical mechanism, which helps children decode and implement the general principles of universal grammar. As previously mentioned, the LAD isn't language-specific. Once the child hears an adult speaking a language, the LAD is triggered, and it will help the child acquire that specific language.

Universal Grammar

Chomsky does not believe that a child from England is born with the innate ability to learn English, or that a child from Japan has a LAD containing Japanese vocabulary. Instead, he suggests that all human languages share many of the same common grammar principles.

For example, most languages:

• Differentiate between verbs and nouns

• Have a way of talking about the past and present tense

• Have a way of asking questions

• Have a counting system

According to Universal Grammar theory, the basic grammatical structures of language are already encoded in the human brain at birth. It is a child’s environment that will determine which language they will learn.

So, let's break down how the LAD supposedly works:

1. The child hears adult speech, which triggers the LAD.

2. The child automatically applies universal grammar to speech.

3. The child learns new vocabulary and applies the appropriate grammar rules.

4. The child is able to use the new language.

Fig 1. According to Universal Grammar theory, the basic grammatical structures of language are already encoded in the human brain at birth.

Language Acquisition Device: Evidence for the LAD

Theorists need evidence to support their theories. Let's look at the two key pieces of evidence for the LAD.

Virtuous errors

When children are first learning a language, they will, of course, make mistakes. These mistakes can give us information as to how children learn. For example, children have an unconscious ability to recognise the past tense and will begin to associate words ending with a /d/ /t/ or /id/ sound with the past. Chomsky suggests this is why children make ‘virtuous errors’ such as, ‘I goed’ rather than ‘I went’ when first learning a language. Nobody taught them to say ‘I goed’; they figured that out for themselves. To Chomsky, these virtuous errors suggest that children are born with the subconscious ability to work out the grammatical rules of language.

The Poverty of Stimulus

In the 1960s, Chomsky rejected the behaviourist theory because children receive ‘impoverished language input’ (baby talk) when growing up. He questioned how children could demonstrate signs of learning grammar before being exposed to sufficient linguistic input from their caregivers.

The poverty of stimulus argument states that children are not exposed to enough linguistic data in their environment to learn every feature of the language. Chomsky suggested that the human brain must have evolved to contain certain linguistic information from birth, which helps children figure out the basic structures of language.

Language Acquisition Device: Criticisms of the LAD

It is important to understand that other linguists hold opposing views of the LAD. Criticism of LAD and Chomsky's theory mainly comes from linguists who believe in the behaviourist theory. Behaviourist theorists are unlike nativist theorists as they argue that children learn language through imitating the adults around them. This theory supports nurture over nature.

Behaviourists argue that there is not enough scientific evidence to support the existence of a language acquisition device. For example, we do not know where the LAD is located in the brain. For this reason, many linguists reject this theory.