What do all languages have in common? - Cameron Morin

View full lesson: https://ed.ted.com/lessons/what-do-all-languages-have-in-common-cameron-morin

Language is endlessly variable. Each of us can come up with an infinite number of sentences in our native language, and we’re able to do so from an early age— almost as soon as we start to communicate in sentences. How is this possible? In the early 1950s, Noam Chomsky proposed a theory that the key to this versatility was grammar. Cameron Morin details Chomsky's theory of universal grammar.

Lesson by Cameron Morin, directed by Eoin Duffy.

Language is endlessly variable.

Each of us can come up with
an infinite number of sentences

in our native language,

and we’re able to do so from an early age—

almost as soon as we start
to communicate in sentences.

How is this possible?

In the early 1950s, Noam Chomsky
proposed a theory

based on the observation that the key
to this versatility seems to be grammar:

the familiar grammatical structure
of an unfamiliar sentence

points us toward its meaning.

He suggested that there are
grammatical rules

that apply to all languages,
and that the rules are innate—

the human brain is hardwired to process
language according to these rules.

He labelled this faculty
universal grammar,

and it launched lines of inquiry
that shaped both the field of linguistics

and the emerging field
of cognitive science for decades to come.

Chomsky and other researchers
set out to investigate

the two main components
of universal grammar:

first, whether there are, in fact,
grammar rules

that are universal to all languages,

and, second, whether these rules
are hardwired in the brain.

In attempts to establish
the universal rules of grammar,

Chomsky developed an analytical tool
known as generative syntax,

which represents the order of words
in a sentence in hierarchical syntax trees

that show what structures are possible.

Based on this tree, we could suggest
a grammar rule

that adverbs must occur in verb phrases.

But with more data,
it quickly becomes clear

that adverbs can appear
outside of verb phrases.

This simplified example illustrates
a major problem:

it takes a lot of data
from each individual language

to establish the rules for that language,

before we can even begin to determine

which rules all languages
might have in common.

When Chomsky proposed universal grammar,

many languages lacked the volume
of recorded samples

necessary to analyze them
using generative syntax.

Even with lots of data,

mapping the structure of a language
is incredibly complex.

After 50 years of analysis, we still
haven’t completely figured out English.

As more linguist data
was gathered and analyzed,

it became clear that languages
around the world differ widely,

challenging the theory that there were
universal grammar rules.

In the 1980s, Chomsky revised his theory

in an attempt to accommodate
this variation.

According to his new hypothesis
of principles and parameters,

all languages shared certain
grammatical principles,

but could vary in their parameters,
or the application of these principles.

For example, a principle is
“every sentence must have a subject,"

but the parameter of whether the subject
must be explicitly stated

could vary between languages.

The hypothesis of principles
and parameters

still didn’t answer the question of which
grammatical principles are universal.

In the early 2000s, Chomsky suggested
that there’s just one shared principle,

called recursion, which means structures
can be nested inside each other.

Take this sentence,

which embeds a sentence within a sentence
within a sentence.

Or this sentence, which embeds
a noun phrase in a noun phrase

in a noun phrase.

Recursion was a good candidate
for a universal grammar rule

because it can take many forms.

However, in 2005 linguists
published findings

on an Amazonian language called Piraha,

which doesn’t appear to have
any recursive structures.

So what about the other part
of Chomsky’s theory,

that our language faculty is innate?

When he first proposed universal grammar,

the idea that there was a genetically
determined aspect of language acquisition

had a profound, revolutionary impact.

It challenged the dominant paradigm,
called behaviorism.

Behaviorists argued that all animal
and human behaviors, including language,

were acquired from the outside
by the mind,

which starts out as a blank slate.

Today, scientists agree that behaviorism
was wrong,

and there is underlying,
genetically encoded biological machinery

for language learning.

Many think the same biology
responsible for language

is also responsible for other
aspects of cognition.

So they disagree with Chomsky’s idea

that there is a specific, isolated,
innate language faculty in the brain.

The theory of universal grammar
prompted the documentation and study

of many languages
that hadn’t been studied before.

It also caused an old idea to be
reevaluated and eventually overthrown

to make room for our growing
understanding of the human brain.