Phonetic notation uses square brackets
[ ] while phonological notation uses slashes / /. For example, in English, the
morpheme "bed" would be represented phonetically as [bed] and phonologically
as /bed/. Likewise, the morpheme "bet" would be represented as [bet]
phonetically and /bet/ phonologically. This is an example of what is called a
minimal opposition or a minimal pair. These two morphemes are recognized as different
in English, but might be perceived as identical in some other language that does
not differentiate between what English-speakers hear as the sounds of "d"
“As soon as a living being
has a memory and a plan, he can give a meaning to what he perceives. Meaning therefore
does not reside in things themselves. It resides in the living being who uses
things to imbue them with meaning. ”
“When we cast a light
on one piece of the world, we extinguish everything on which we have not cast
that light. This is how we create the things we say: to speak is to create a piece
of the world; it is to mould it, to make it, and to make it live.”
The content of a spoken message
depends not only on the factual meaning of the words and the prosody
(intonation) with which they are spoken, but also on non-linguistic codes such
as hand gestures and other body movements. Think of just how well mimes, for example,
manage to communicate with non-linguistic codes alone.
That is why,
if someone speaks a sentence to you over the telephone, it will be less rich in
meaning than if they had spoken that same sentence to you in person. That is also
why the same sentence, in written form, will have even less potential meaning
than if you heard it over the telephone. The tendency of many people to use “smilies”
in their e-mails represents an attempt to restore the prosodic dimension to their
THE CONNECTIONS BETWEEN THOUGHT AND LANGUAGE
When someone is speaking to
you, they do not separate each word from the next with a pause, like the spaces
words on a page, yet your brain can still recognize each word individually.
This ability is truly remarkable. (To realize just how hard it really is to isolate
the components of spoken language, just try listening to someone speaking a language
that you don’t know at all.)
In linguistics, the smallest unit
of meaning, corresponding roughly to a word, is called a morpheme.
To recognize words or morphemes from their sounds, the brain breaks them down
into phonemes: the smallest units of sound that are used to construct the
words of a given language.
There are two different
disciplines that study the role of sounds in language. These disciplines are historically
related to each other, but one is more relevant than the other for understanding
the language functions of the brain.
The first of
these disciplines is phonetics, which describes and classifies the sounds
of all languages according to the way that these sounds are physically produced
by our organs of speech. In phonetics, the sounds of words are represented by
symbols placed between square brackets: [ ] (see the first sidebar on this page
for an example). Examples of studies in phonetics would include a comparison of
the use of different sounds in different languages, or a description of how the
sounds in a given language have evolved.
discipline is phonology, which historically grew out of phonetics. Phonology
is not interested in describing the sounds of language so precisely as phonetics,
but is interested in examining the internal structure specific to a given language.
In phonology, what is important is not the sound itself, but rather the way that
it compares and contrasts with other sounds in the same phonological table typifying
a given language. Phonological descriptions of words are represented by symbols
between slashes: / / (see the first sidebar on this page for an example). Thus
it is phonological analysis that lets us study the cerebral substrate of linguistic
encoding and decoding with words, sentences, and meanings in a given language.
ultimate function of language is to convey meaning. Once a word has been recognized
from its phonemes, its meaning will depend on several factors: what it designates
in the world, the
context in which it is being spoken, and, most important, the way that it
fits together with its neighbours in the sentence—that is, its syntax.
The order of the words in a sentence can be extremely important. The
English sentences “The man eats the alligator.” and “The alligator
eats the man.” contain the same words but mean two very different things.
Only the order of the two nouns, and hence their relationship to the verb, has
In every language, there are certain words
that mean nothing in themselves but perform a syntactic function in the sequence
of words that constitutes a sentence. The usefulness of these “relational”
words, such as and, the, a, and with, becomes
especially clear when they are left out, sometimes causing inadvertently comic
ambiguities, in contexts such as classified advertisements or newspaper headlines
where space is at a premium (“Bicyclist struck by car in fair condition.”
“Nuns forgive break-in, assault suspect.”)
The American linguist
Chomsky demonstrated the importance of syntax in natural languages with his
famous sentence “Colorless green ideas sleep furiously.” Obviously,
this sentence has no real meaning, but its syntax is so correct that we try to
find one anyway. Such observations led Chomsky to formulate his theory of universal
grammar (follow the Tool module link to the left). According to this theory, syntax
is independent of meaning, of context, of the information
stored in the speaker’s memory, and of what the speaker wants to communicate.
Chomsky’s approach is disputed, however, by linguists such as George Lakoff,
who instead regard conceptual metaphors based on our bodily experiences as the
central feature of language.
Be that as it may, the
words that we know form a mental lexicon where each word can evoke several different
meanings depending on the context in which is is spoken. When we speak, each word
is thus related to several other words with which it shares connected meanings.
This is what enables the brain to construct categories.
is one of the most important aspects of language. Without our ability to group
similar objects into categories, language would be an infinite set of nouns designating
specific objects. In other words, it would be impossible.
The most valuable
thing about categorization is that it lets us create concepts— general,
abstract mental representations. And concepts in turn make language a tool that
lets us expand our cognitive capacities so that we can apply them more effectively
to better understand the world.
experiments have shown that language enables this transformation of information
into abstract representations. For example, if a group of people listen to several
sentences that form a paragraph, most of these people will then be able to state
the general idea of the paragraph in their own words, but not to repeat the exact
sentences they heard. It is as if two transformations have taken place. In the
first, the people took the sentences that they heard and represented them mentally
in more abstract, consolidated terms, which seem easier to memorize. In the second,
the people retrieved this more abstract representation and converted it into their
Scientists are still debating whether the
meaning of a word and the characteristics of the real-world object that it designates
are stored in the same location in the brain. Some researchers believe that there
is a single storage site for every individual concept, idea, or object. For instance,
all of the characteristics of lions would be stored together in one area of the
brain, and the audible and written forms of the word “lion” would
be stored in other areas that were connected to the one where this animal’s
characteristics were stored.
But other scientists believe that information
is processed in the brain in
a much more distributed fashion: the lion’s smell, roar, and physical
appearance would thus be stored in many areas of the brain that were closely interconnected.
Thus, when you heard or read the word “lion”, all of these areas would
be activated simultaneously.
In addition to its fundamental role in
communication, language also gives us a powerful internal mechanism for retrieving,
critiquing, and changing our thoughts. This internal mode of communication enables
us to perform more complex mental operations in both the logical and the affective
spheres. And the ability to predict consequences from these conceptual operations
provides a definite adaptive advantage to a social species such as our own.
Brain-imaging studies have shown
that within the brain, language is organized according to semantic categories
and not according to words. For example, depending on whether you ask the participants
in an experiment to name people, or animals, or tools, you will observe increased
activity in different
regions of the temporal cortex. This form of organization also explains
why relatively small lesions in the left temporal lobe sometimes result in the
loss of the words that designate one particular category of objects, but not others.
When a child is one year old, the
temporal lobe that includes Wernicke’s
area is still very immature and has scarcely more than 50% of the surface
area that it will have when the child becomes an adult. Moreover, the central
part of this lobe, which in adults is associated with lexical storage, is scarcely
20% of its adult size. The same thing goes for the inferior
parietal lobule, which is connected to Wernicke’s area and enables words
to be assigned to visual, auditory, and somatosensory events. The neurons of this
lobule show relatively little myelinization
during the first year of life, and its surface is less than 40% of an adult’s.
By the age of about 20 months, when the child can speak nearly 100 words
and understand twice as many, the surface of the temporal lobe has grown to about
65% of an adult’s. At age 30 months, when the child has mastered about 500
words, its temporal lobe is 85% of the size of an adult’s.
maturation of Wernicke’s area thus seems to be one factor that contributes
to the growth of a child’s lexical capacities.
Procedural (implicit) memory for
language depends on the integrity of the cerebellum,
the corpus striatum, and other basal
ganglia, as well as on a particular area in the left perisylvian cortex. Implicit
language skills also seem to call on the limbic
system, which governs emotions and motivations.
(explicit) memory, on the other hand, depends on the integrity of the hippocampus,
the medial temporal lobe, and large areas of the associative cortex in both hemispheres.
The neuronal phenomenon of the activation
threshold is not associated with any particular system of the brain but
affects all the higher functions, including language skills. The neural substrate
of any mental representation requires a certain frequency of nerve impulses to
reach its activation threshold, that is, to generate action potentials itself. Whenever someone uses a particular word or
syntactic construction, their activation threshold for it is lowered and its subsequent
reuse is facilitated. Conversely, if a neural circuit remains inactive, its activation
threshold gradually increases. The same effects are also seen at the molecular
level, on two phenomena that play a role in the activation threshold: long-term
potentiation (LTP) and long-term
LEARNING TO SPEAK A FIRST AND SECOND LANGUAGE
Research by authors such
as the American linguist Noam Chomsky has shown that for human language to be
as sophisticated as it is, the brain must contain some mechanisms that are partly
preprogrammed for this purpose (follow the Tool module link to the left). Babies
are born with a language-acquisition faculty that lets them master
thousands of words and complex rules of grammar in just a few years. This
is not the case for our closest primate cousins, who have never succeeded in learning
more than a few hundred symbols and a few simple sentences (follow the Experiment
module link to the left).
ability to retain such an impressive number of words involves two different types
of memory, depending on whether the language in question is our mother tongue
or a second language that we learned later in life (follow the Tool module link
to the left).
To learn our mother tongue, we rely on procedural
memory (also known as implicit memory), the same kind that is involved when
we learn skills that become automatic, like riding a bike or tying our shoelaces.
Because we are so immersed in our mother tongue, we end up using it just as automatically,
without even being aware of the rules that govern it.
In contrast, to learn
a second language, we must usually make a conscious effort to store the vocabulary
and the grammatical rules of this language in our memories. When learned in this
way, a second language depends on declarative
memory (also known as explicit memory). Sometimes, however, people learn a
second language “in the street” without having to pay much attention.
In this case, the learning process is much the same as it was for their first
language and, as in that case, is handled by procedural memory.
the more the method used to teach a second language is based on communicating
and practicing, the more the students who learn it will rely on procedural memory
when using it. Conversely, the more formal and systematic the method used to teach
the second language, the more the students will rely on declarative memory.
and using a language may thus involve applying either implicit linguistic skills
or explicit metalinguistic knowledge. Because each of these skill sets is supported
by different structures in the brain (see sidebar), language disorders can affect
people’s first languages and second languages selectively. Following brain
injuries, bilingual people may selectively lose the use of one of their two languages.
But the language that they retain is not necessarily their mother tongue, nor
is it necessarily the language that they spoke most fluently before their accident.
Some types of brain damage can make people amnesic without affecting
their ability to speak their mother tongue (which depends on procedural memory).
But other types can cause serious problems in someone’s automatic use of
speech without affecting their ability to remember a language that they learned
consciously (using declarative memory). Other observations have been made that
reflect this same distinction. For example, some people who have aphasia seem
to recover their second language more successfully than their first, whereas some
people with amnesia lose access to their second language completely. Alzheimer’s
patients retain those language functions based on procedural memory but lose those,
such as vocabulary, that are based on declarative memory.
even in one’s mother tongue, not all aspects of language rely on procedural
memory. It is believed, for example, that the lexicon for a person’s first
language, which consists of the association of groups of phonemes with meanings,
may have close connections with declarative memory. Vocabulary thus seems to constitute
a special aspect of language: the great apes are capable of learning a large number
of symbols related to words (follow the Experiment module link to the left); “wild
children” who are deprived of language at the start of their lives can
also learn many words, but comparatively little syntax; and people who have anterograde
amnesia, though they can acquire new motor or cognitive skills, cannot learn
While the lexicon for a person’s first language depends
on declarative memory, which involves the parietal and temporal lobes, the grammar
of this language depends on procedural memory, which involves the frontal lobes
and the basal
ganglia. Procedural memory is used for unconscious learning of motor and cognitive
skills that involve chronological sequences of operations. This description clearly
applies to grammatical operations, which consist in sequencing the lexical elements
of a language in real time.
area and the
supplementary motor area and the premotor cortex of the left hemisphere, all
of which participate in the production of language, are activated when you repeat
words mentally without saying them out loud. In this way, you continually refresh
your “phonological buffer” and thus increase the time that you can
hold this information in your verbal memory. Thus these frontal areas of the left
hemisphere are involved in actively maintaining information in working
Some studies of children with reading problems have shown
that these problems were actually due to difficulties in understanding syntax,
which were in turn caused by deficiencies in the children’s working memory.
It is also working memory that lets you understand especially long or
complex sentences such as “The clown who is carrying the little boy kisses
the little girl.” More specifically, working memory lets you keep this verbal
information in mind long enough for the sequence of words in the sentence to assume
Simultaneous interpretation may
well be the most complex verbal task imaginable. To take a speech that is being
delivered in one language and simultaneously translate it into another language
orally, the interpreter must understand the words that the speaker is saying,
hold them in working
memory while encoding them into the other language, then speak them in
this other language. At the same time, the interpreter must continue listening
to the speaker so as to be able to keep repeating this process as the speech goes
Some famous dyslexics include
Einstein, Rodin, Edison, Pasteur, Andersen, and Leonardo da Vinci. In fact, throughout
his life, Da Vinci wrote in “mirror script”. When you think about
what these geniuses achieved, it almost makes you wish you were dyslexic.
One of the rarest and strangest
types of aphasia is foreign-accent syndrome, of which fewer than 20 cases have
been reported over the past 80 years. From one day to the next, people who come
down with this syndrome suddenly start speaking with what sounds like a strong
foreign accent. In one case, a woman who was born in Boston, had lived her entire
life there, had never travelled overseas, and had never learned a language other
than English woke up one morning speaking it as if her first language were French!
But a subsequent acoustic analysis of her speech showed that she was not
really speaking with a French accent. In reality, she had developed a speech-production
disorder that resulted in an acoustical spectrum similar to that of an American
comedian imitating a French accent.
Small lesions in various regions
of the brain might be the underlying cause of the subtle changes in pronunciation
(longer syllables, different tonalities, and so on) that create the impression
of a foreign accent.
The existence of foreign-accent syndrome does not
mean that there might be an “accent zone” in the brain, but it does
give us some indications about the way that language is produced.
How brain damage will affect language
use in bilingual people is hard to predict. Factors that may
influence whether a bilingual person recovers the use of one or both languages
include the order in which they were learned, the person’s ease of expression
in each of them, and which language the person used the most recently.
We know, for example, that if the person learned both languages at the same time,
the damage will usually affect both languages in the same way. But if the person
learned the two languages at different times, one will likely be more affected
than the other.
consists of various degrees of difficulty in learning to read and write. This
is a developmental disorder that is discovered when children are learning to read
(around age 6 or 7) and that is more common among boys and among children who
(Some reading problems can be acquired in adult life, as the result of brain injuries,
in which case they are referred to as alexia.)
People with dyslexia
may confuse certain sounds (for instance, p with b, or f with v) or letters that
are visually similar (such as m and n). To dyslexics, some letters may seem reversed
(perhaps a d that looks like a b) or even words may appear so (“bag”
looks like “gab”). In cases of what is known as profound dyslexia,
when people read out loud, they will actually substitute one word for another
with a related meaning (for example, read “cow” in place of “horse”).
Dyslexics represent 5 to 10% of the total population, and their other
cognitive abilities are completely normal. The severity of this disorder varies
widely; some dyslexics have only slight trouble in reading, while others are completely
Dyslexics may be able to express themselves orally in a
completely normal way, but the problem begins when they are confronted with written
words. However, the nature of dyslexia is probably more complex than a simple
difficulty in reading. Some authorities even regard it as more of a problem in
sensory processing, while others consider it a memory disorder. The purpose of
most research on dyslexia is to establish the entire chain of causal links between
certain genes, certain parts of the brain, certain cognitive functions, and the
ability to read and write.
Thus researchers have begun to identify various
signs of pathology in the brains of dyslexics. For example, some obvious abnormalities
have been reported in the arrangement of cortical cells, especially in certain
areas of the left frontal and temporal cortexes. The scientists who uncovered
these unusual cellular configurations in language-related areas of the brain believe
that they probably start developing in the middle period of fetal gestation, when
cell migration is observed in the cerebral cortex.
In most people,
temporal planum is considerably larger than the right. But some authors say
that in dyslexics, these two structures are similar in size. The presence or absence
of temporal planum asymmetry in dyslexics remains a controversial topic, however.
When differences in age, sex, and overall brain size are taken into account, the
anatomical differences between the temporal planum in dyslexics and in control
groups are far smaller.
Other studies suggest that some changes in dyslexics’
sensory pathways may be responsible for their problems with reading. Autopsies
have shown that in dyslexics, the neurons in the magnocellular
layers of the lateral geniculate nucleus were smaller than in control groups
and were arranged in a disorganized fashion. These abnormalities might interfere
with the rapid processing required for changing visual signals such as those involved
Brain-imaging studies of dyslexics have shown reduced activity
area V5/MT, which is responsible for detecting movement, or in the lower part
of the left temporal lobe.
on the extent of the brain damage that causes them, the various forms of aphasia
range from subtle speech impairments to a complete inability to speak.
People with global aphasia can manage to pronounce
just a very few words, unconnected by any syntax. At best, global aphasics have
an automatic form of expressive language, composed especially of emotional exclamations.
They may also still have control over facial expressions, hand gestures, and vocal
intonations. Their prognosis for recovering use of language is nevertheless extremely
In conduction aphasia, language comprehension
and spontaneous oral expression are normal, but individuals have a great deal
of difficulty when asked to repeat words or phrases.When they try to do so, they
mix up the sounds in words and make numerous transformations and omissions of
The location of the brain lesions that cause conduction aphasia
is still controversial. Wernicke, and later Geschwind, believed that conduction
aphasia was caused by the destruction of the arcuate
fasciculus, the fibre bundle, in the suprasylvian parietal cortex, that connects
Wernicke’s area to Broca’s area. But other authors have proposed that
the symptoms of conduction aphasia might be produced by dysfunctions in areas
such as the auditory cortex, the insula, and the supramarginal gyrus.
In anomic aphasia (also known as nominal aphasia), oral expression
and syntactic structure remain intact, and the main difficulty is in finding certain
words. People with anomic aphasia compensate for their trouble in finding the
right words by using other, vaguer words such as “thing” or “whatsit”,
or they may use circumlocutions such as “the instrument that you wear on
the wrist and that tells you the time”. If you show someone with anomic
aphasia a photo of John F. Kennedy, for example, she may say that he was president
of the United States, and that he was assassinated, but will not find his name
until you help her by hinting “John F… ”. It is still possible
to communicate with anomic aphasics, however, if you know the context or subject
of the conversation.
Anomic aphasia is often caused by parietal lobe
damage that is limited to the angular
gyrus or the area just above it. This disorder has also been associated with
damage to the pulvinar in the thalamus. Because the language processing system
in the human brain forms a densely interconnected network, damage just about anywhere
in the left hemisphere can cause some form of anomic aphasia. Depending on the
location of the lesion, an individual may, for example, be unable to name an item
when it is shown to him (because of a disconnection between the visual cortex
and the inferior parietal cortex) but still be able to name it if he is allowed
to touch it or if it is described to him out loud (if the auditory and tactile
pathways to the parietal cortex remain intact).
Many other, less common
forms of aphasia have also been described. In alexia, caused
by damage to the inferior part of the left occipital and temporal lobes, the individual
cannot read but can still write. In agraphia, the individual
can reason normally, but cannot write. In anarthria, a malfunction
in the system that controls the motor aspects of speech prevents individuals from
articulating the words that would convey their thoughts. Progressive aphasia
develops insidiously, resulting in a gradually worsening loss of speech.
Subcortical aphasia is caused by small lesions in the subcortical
areas of the left hemisphere and presents a variety of the symptoms seen in other
kinds of aphasia. Transcortical motor aphasia (TMA)
is characterized by abnormalities in spontaneous expression but distinguished
from Broca’s aphasia in that people with TMA can repeat long sentences,
whereas Broca’s aphasics can repeat only simple words.
that each of these different types of aphasia typically includes several subtypes
clearly shows just how complex language pathologies can be.
In deaf people who use sign language,
left hemisphere damage can cause language deficits comparable to those observed
in verbal aphasics. For example, in some cases very similar to Broca’s aphasia,
it becomes very difficult for people to sign, even though neither their comprehension
nor their non-sign-language gestures are impaired.
Likewise, there is
a manifestation of Wernicke’s aphasia that occurs in deaf people. In these
cases, people can still sign fluently, but make frequent mistakes, and they have
difficulty in understanding other people’s signs.
There was also
one very rare case involving a man who could speak but also knew sign language
because his parents were deaf. After suffering a left-hemisphere stroke, he displayed
global aphasia, from which he recovered gradually. Interestingly, he recovered
his ability to express himself in both spoken language and sign language at the
same time. Other studies have shown that the two areas of the left hemisphere
that are involved in these two types of language overlap, though not completely.