CHAPTER I
INTRODUCTION
Linguistic study involves a search
for patterns in the way speakers use language; linguists aim to describe these
patterns by reducing them to a set of rules called a grammar. As Edward Sapir
once commented, however, “All grammars leak” (1921, 38). Over time linguists
came to recognize a growing number of language components; each new component
was an attempt to plug the “leaks” in an earlier grammar, to explain what had
previously resisted explanation. The following discussion pinpoints the various
leaks linguists have recognized (as well as their attempts to plug the leaks)
and demonstrates how culture and language influence each othe
r.
Before going into the details of
language and its processing one should have a rough idea of “what the various
brain parts are? “ It is common knowledge that the brain controls muscular
activity in human body. It is clear that the brain is also the seat of
conscious thought. Indeed we can all agree that when we have an idea, make the
unconscious decision to convey it in language and subsequently actually produce
some utterances in our language; the brain is involved at every step along the
way. Here we will take a look at the important parts of brain as far as
language is concerned.
Frontal Lobe:
This is the front part of our brain. The frontal lobes are considered our
emotional control center and home to our personality. The frontal lobes are
involved in motor function, problem solving, spontaneity, memory, language,
initiation, judgments, impulse control, and social and sexual behavior.
Parietal Lobe:
The parietal lobes can be divided into two functional regions. One involves
sensation and perception and the other is concerned with integrating sensory
input, primarily with the visual system.
Occipital Lobe:
The posterior lobe of each cerebral hemisphere, having the shape of 3 sided
pyramid. It contains the visual center of the brain.
Temporal Lobe:
The lower lateral lobe of either cerebral hemisphere, located in front of
occipital lobe. It contains the visual center of the brain.
Cerebrum:
It is the largest part of the brain as a whole. It is here that things like
perception, imagination, thought, judgment, and decision occur.
Cerebellum:
Cerebellum is involved in coordination of movement and motor learning.
Broca’s area:
Region located anteriorly in the left hemisphere in the left frontal lobe
operculum. It is responsible for production of words and sentences. This area
is named after Paul Broca (in 1861).
Wernicke’s area:
Region located posteriorly in the left hemisphere in the superior temporal
gyrus. It is responsible for comprehension of spoken words and sentences. This
area is named after Carl Wernicke (in 1874)
CONTENT
1. CHAPTER
I: INTRODUCTION .................................................... 1
2. CONTENT........................................................................................
3
3. CHAPTER
II: DISCUSSION..........................................................
4
A.
COMPONENT OF LANGUAGE..............................................
4
B.
LANGUAGE PROCESSING.................................................... 8
4. CONCLUSION
............................................................................... 15
5. REFERENCES
................................................................................ 16
CHAPTER II
DISCUSSION
A. COMPONENT
OF LANGUAGE
Phonology: Sounds
The study of the sounds of language
is called phonology. The sounds of human language are special because they are
produced by a set of organs, the speech organs, that belong only to the human
species. The actual sounds that come out of our mouths are called phones, and
they vary continuously in acoustic properties. However, we hear all the phones
within a particular range of variation as functionally equivalent allophones of
the same phoneme, or characteristic speech sound, in the language. Part of the
phonologist"s job is to map possible arrangements of speech organs that
human beings may use to create the sounds of language. Another part is to
examine individual languages to discover the particular sound combinations they
contain and the patterns into which those sound combinations are organized. No
language makes use of all the many sounds the human speech organs can produce,
and no two languages use exactly the same set. American English uses only 38
sounds. Most work in phonology has been done from the perspective of the
speaker, who produces, or articulates, the sounds of language using the speech organs.
Although
all languages rely on only a handful of phonemes, no two languages use exactly
the same set. Furthermore, different speakers of the same language often differ
from one another in the way their phonemes are patterned, producing
"accents," which constitute one kind of variety within a language.
This variety is not random; the speech sounds characteristic of any particular
accent follow a pattern. Speakers with different accents are usually able to
understand one another in most circumstances, but their distinctive
articulation is a clue to their ethnic, regional, or social-class origins. The
sound changes that occur over time within any particular phonemic system
(accent) are equally orderly.
Morphology: Word Structure
Morphology,
the study of how words are put together, developed as a subfield of linguistics
as soon as linguists realized that the rules they had devised to explain sound
patterns in language could not explain the structure of words.
What is a word? English speakers
tend to think of words as the building blocks of sentences and of sentences as
strings of words. But words are not all alike: some words (book) cannot be
broken down into smaller elements; others (bookworm) can. The puzzle deepens
when we try to translate words from one language into another. Sometimes
expressions that require only one word in one language (préciser in
French) require more than one word in another (to make precise in
English). Other times, we must deal with languages whose utterances cannot
easily be broken down into words at all. Consider the utterance nikookitepeena
from Shawnee (an indigenous North American language), which translates into
English as "I dipped his head in the water" (Whorf 1956, 172).
Although the Shawnee utterance is composed of parts, the parts do not possess
the characteristics we attribute to words in, say, English or French.
To make
sense of the structure of languages such as Shawnee, anthropological linguists
needed a concept that could refer to both words (like those in the English
sentence above) and the parts of an utterance that could not be broken down
into words. This led to the development of the concept of morphemes,
traditionally defined as "the minimal units of meaning in a
language." The various parts of a Shawnee utterance can be identified as
morphemes, and so can many English words. Describing minimal units of meaning
as morphemes, and not as words, allows us to compare the morphology of
different languages.
Morphemic patterning in languages like Shawnee may seem hopelessly
complicated to native English speakers, yet the patterning of morphemes in
English is equally complex. Why is it that some morphemes can stand alone as
words (sing, red) and others cannot (-ing, -ed)? What determines a word
boundary in the first place? Words, or the morphemes they contain, are the
minimal units of meaning. Thus, they represent the fundamental point at which
the arbitrary pairing of sound and meaning occurs.
Syntax: Sentence Structure
A third
component of language is syntax, or sentence structure. Linguists began to
study syntax when they discovered that morphological rules alone could not
account for certain patterns of morpheme use. In languages like English, for
example, rules governing word order cannot explain what is puzzling about the
following English sentence: "Smoking grass means trouble." For many
native speakers of American English, this sentence exhibits what linguists call
structural ambiguity. That is, we must ask ourselves what trouble means: the
act of smoking grass (marijuana) or observing grass (the grass that grows on
the prairie) that is giving off smoke. In the first reading, smoking is a
gerund working as a noun; in the second, it is a gerund working as an
adjective.
We can
explain the existence of structurally ambiguous sentences if we assume that the
role a word plays in a sentence depends on the overall structure of the
sentence in which the word is found and not on the structure of the word
itself. Thus, sentences can be defined as ordered strings of words, and those
words can be classified as parts of speech in terms of the function they
fulfill in a sentence. But these two assumptions cannot account for the
ambiguity in a sentence like "The father of the girl and the boy fell into
the lake." How many people fell into the lake? Just the father or the
father and the boy? Each reading of the sentence depends on how the words of
the sentence are grouped together. Linguists discovered numerous other features
of sentence structure that could not be explained in terms of morphology alone,
leading to a growth of interest in the study of syntactic patterns in different
languages. Although theories of syntax have changed considerably since
Chomsky"s early work, the recognition that syntax is a key component of
human language structure remains central to contemporary linguistics.
Semantics:Meaning
Semantics, the study of meaning, was avoided by linguists for many years because meaning is a highly ambiguous term. What do we mean when we say that a sentence means something? We may be talking about what each individual word in the sentence means or what the sentence as a whole means or what I mean when I utter the sentence, which may differ from what someone else would mean even if uttering the same sentence. In the 1960s, formal semantics took off when Chomsky argued that grammars needed to represent all of the linguistic knowledge in a speaker"s head, and word meanings were part of that knowledge. Formal semanticists focused attention on how words are linked to each other within a language, exploring such relations as synonymy, or "same meaning" (old and aged); homophony, or "same sound, different meaning" (would and wood); and antonymy, or "opposite meaning" (tall and short). They also defined words in terms of denotation, or what they referred to in the "real world."
Semantics, the study of meaning, was avoided by linguists for many years because meaning is a highly ambiguous term. What do we mean when we say that a sentence means something? We may be talking about what each individual word in the sentence means or what the sentence as a whole means or what I mean when I utter the sentence, which may differ from what someone else would mean even if uttering the same sentence. In the 1960s, formal semantics took off when Chomsky argued that grammars needed to represent all of the linguistic knowledge in a speaker"s head, and word meanings were part of that knowledge. Formal semanticists focused attention on how words are linked to each other within a language, exploring such relations as synonymy, or "same meaning" (old and aged); homophony, or "same sound, different meaning" (would and wood); and antonymy, or "opposite meaning" (tall and short). They also defined words in terms of denotation, or what they referred to in the "real world."
The
denotations of words like table or monkey seem fairly straightforward, but this
is not the case with words like truth or and. Moreover, even if
we believe a word can be linked to a concrete object in the world, it may still
be difficult to decide exactly what the term refers to (a challenge to which
Hockett"s design feature of "semanticity" draws attention).
Suppose we decide to find out what monkey refers to by visiting the zoo. In one
cage we see small animals with grasping hands feeding on fruit. In a second
cage are much larger animals that resemble the ones in the first cage in many
ways, except that they have no tails. And in a third cage are yet other animals
who resemble those in the first two cages, except that they are far smaller and
use their long tails to swing from the branches of a tree. Which of these
animals are monkeys?
To answer
this question, the observer must decide which features of similarity or
difference are important and which are not. Having made this decision, it is
easier to decide if the animals in the first cage are monkeys and whether the
animals in the other cages are monkeys as well. But such decisions are not easy
to come by. Biologists have spent the last 300 years or so attempting to
classify all living things on the planet into mutually exclusive categories. To
do so, they have had to decide, of all the traits that living things exhibit,
which ones matter.
This
suggests that meaning must be constructed in the face of ambiguity. Formal
linguistics, however, tries to deal with ambiguity by eliminating it, by
"disambiguating" ambiguous utterances. To find a word"s
"unambiguous" denotation, we might consult a dictionary. According to
the American Heritage Dictionary, for example, a pig is "any of
several mammals of the family Suidae, having short legs, cloven hoofs,
bristly hair, and a cartilaginous snout used for digging." A formal
definition of this sort does indeed relate the word pig to other words in
English, such as cow and chicken, and these meaning relations would hold even
if all real pigs, cows, and chickens were wiped off the face of the earth. But
words also have connotations, additional meanings that derive from the typical
contexts in which they are used in everyday speech. In the context of antiwar
demonstrations in the 1960s, for example, a pig was a police officer.
From a
denotative point of view, to call police officers pigs is to create ambiguity
deliberately, to muddle rather than to clarify. It is an example of metaphor, a
form of figurative or nonliteral language that violates the formal rules of
denotation by linking expressions from unrelated semantic domains. Metaphors
are used all the time in everyday speech, however. Does this mean, therefore, that
people who use metaphors are talking nonsense? What can it possibly mean to
call police officers pigs?
We cannot
know until we place the statement into some kind of context. If we know, for
example, that protesters in the 1960s viewed the police as the paid enforcers
of racist elites responsible for violence against the poor and that pigs are
domesticated animals, not humans, that are often viewed as fat, greedy, and
dirty, then the metaphor "police are pigs" begins to make sense. This
interpretation, however, does not reveal the "true meaning" of the
metaphor for all time. In a different context, the same phrase might be used,
for example, to distinguish the costumes worn by police officers to a charity
function from the costumes of other groups of government functionaries. Our
ability to use the same words in different ways (and different words in the same
way) is the hallmark of openness, and formal semantics is powerless to contain
it. This suggests that much of the referential meaning of language escapes us
if we neglect the context of language use.
B. LANGUAGE PROCESSING
Language processing refers to the way
human beings use words to communicate ideas and feelings, and how such
communications are processed and understood. Thus it is how the brain creates
and understands language.
Most recent theories consider that this process is carried out entirely by and
inside the brain. This is considered one of the most
characteristic abilities of the human species - perhaps
the most characteristic. However very little is known about it and there is
huge scope for research on it.
Most of the knowledge acquired to
date on the subject has come from patients who have suffered some type of
significant head injury, whether external (wounds, bullets) or
internal (strokes,
tumors, degenerative diseases). Studies have shown
that most of the language processing functions are carried out in the cerebral
cortex. The essential function of the cortical language areas is symbolic representation. Even though
language exists in different forms, all of them are based on symbolic
representation.
Much of the language function is
processed in several association areas, and there are two
well-identified areas that are considered vital for human communication:
Wernicke's
area and Broca's area. These areas are usually located
in the dominant hemisphere (the
left hemisphere in 97% of people) and are considered the most important areas
for language processing. This is why language
is considered a localized and lateralized function.
However, the less-dominant hemisphere also participates in this cognitive function, and there is ongoing debate
on the level of participation of the less-dominant areas.Other factors are
believed to be relevant to language processing and verbal fluency, such as
cortical thickness, participation of prefrontal areas of the cortex, and
communication between right and left hemispheres.
Wernicke's area
Lateral surface of the brain with Brodmann's areas numbered.
Wernicke's area is classically located in the posterior section of the superior temporal
gyrus of the
dominant hemisphere (Brodmann area 22), with some branches extending
around the posterior section of the lateral sulcus, in the parietal lobe.[4]
Considering
its position, Wernicke's area is located relatively between the auditory cortex and the visual cortex. The former is located in the transverse temporal
gyrus (Brodmann
areas 41 and 42), in the temporal lobe, while the latter is located in the posterior section of
the occipital lobe (Brodmann areas 17, 18 and 19).[4]
While the
dominant hemisphere is in charge of most of language comprehension, recent
studies have demonstrated that the less dominant (right hemisphere in 97% of
people) homologous area participates in the comprehension of ambiguous words,
whether they are written or heard.[5]
Receptive speech has traditionally been associated
with Wernicke's area of the posterior superior temporal gyrus (STG) and
surrounding areas. Current models of speech perception include greater
Wernicke's area, but also implicate a "dorsal" stream that includes
regions also involved in speech motor processing.[6]
First
identified by Carl Wernicke in 1874, its main function is the
comprehension of language and the ability to communicate coherent ideas,
whether the language is vocal, written, signed.[2]
Broca's area
Broca's area is usually formed by the pars triangularis and the pars opercularis of the inferior frontal
gyrus (Brodmann areas 44 and 45). It follows Wernicke's area, and as such they both are usually located in the left
hemisphere of the brain.[4]
Broca's
area is involved mostly in the production of speech. Given its proximity to the motor cortex, neurons from Broca's area send signals to the larynx, tongue and mouth motor areas, which in turn send the signals to the
corresponding muscles, thus allowing the creation of sounds.[4]
A recent
analysis of the specific roles of these sections of the left inferior frontal
gyrus in verbal fluency indicates that Brodmann area 44 (pars opercularis) may
subserve phonological fluency, whereas the Brodmann area 45 (pars triangularis)
may be more involved in semantic fluency.[7]
Arcuate fasciculus
Diffusion tensor
imaging image of
the brain showing the right and left, also shown are the right and left superior
longitudinal fasciculus
and tapetum of corpus
callosum. Image
provided by Aaron G. Filler, MD, PhD.
Arcuate fasciculus is a bundle of nerves that is believed to connect the
posterior part of the temporal-parietal junction with the frontal lobe in the brain, which roughly translates into connecting Wernicke's area with Broca's area, thus becoming an important association area.[8]
New research demonstrates that the arcuate fasciculus
instead connects posterior receptive areas with motor areas, and not to Broca's
area in particular. Since some branches of the arcuate fasciculus extend
further into the parietal lobe, it is believed that it has an
important role in attention.[8]
Other brain areas involved in language
processing
Along with the Broca’s area and
Wernicke’s area, many other brain parts are involved in language related tasks.
These areas include both LH and RH parts.
LH parts:
Anterior temporal lobe: It is not directly involved
in processing the syntactic or semantic structure of sentence but is primarily
responsible for the initial encoding of word. It causes atleast semantic
information to stay longer active.
Motor activations:
Left
inferior frontal gyrus Traditional Broca’s area as well as
motor cortex are generally involved for the syntactic complexity.
Right
cerebellum It is assumed that the cerebellum forms part of an
articulatory rehearsal mechanism. It has been activated during various verbal
fluency tasks. Cerebellum plays an important role in the cognitive aspects of
motor learning and planning. Also it is activated with error detection tasks.
Left
superior frontal gyrus, This was also found to be
activated with above mentioned areas for syntactic ambiguity and some error
handling tasks.
Superior
frontal gyrus Syntactically ambiguous sentences caused activation
in this area. It was also found to be activated with semantic evaluation of
complex sentences.
RH parts:
Auditory speech processing activates RH as much as
LH. Reading words may also activate some parts of RH.
Right
anterior temporal lobe, More activated for sentences than
for words.
Right
superior temporal gyrus, Activations were experienced for
sentence comprehensions.
Frontal
lobe of RH Comprehension, of lexical semantic ambiguities.
Also it found some role in constructing other kind of alternative interpretations;
primarily semantic.
Effective
use of lexical semantics in sentence comprehension may be partially dependent
on RH particularly right anterior temporal lobe. Right anterior temporal lobe
has an access to lexical information which may not be available to LH. The
normal language comprehension involves a much wider network of Brain areas
carrying out different components of processing, than was earlier assumed.
Broca’s area appears to be more important in maintaining information about both
lexical items and phrases. The motor areas are recruited during the processing
of more demanding sentences. When semantic processing becomes more difficult
additional areas of left and right frontal lobe are activated.
Studies on sign language users
Sign languages (such as ASL) encompass
the same abstract capabilities as spoken languages and contain different levels
of linguistic representation such as phonology, morphology, syntax, semantics
and pragmatics. Such structural similarities between signed and spoken languages
predict that the left hemisphere language areas should also be recruited during
sign language processing. The two forms of language differ in their
input-output modalities. By this view left hemisphere should not be fully
recruited. Right hemisphere plays a greater role in visual spatial processing.
Some observations show that LH plays a
crucial role in supporting sign language. Hickok, Bellugi and Klima [2001]
mentioned in their paper such observation. Deaf signers with comprehension
difficulties had damage to areas that include Wernicke’s area and Patient
with trouble in making signs had damage that involved Broca’s area. Studies
showed that most impaired signers had damage to brain’s left temporal lobe,
where Wernicke’s area is located. Various results establish that LH language
areas are recruited by language system, independent of modality and surface properties
of the language. The organization of brain doesn’t appear to effect particularly
by the way in which language is perceived and produced. One exception to LH’s
monopoly on language production is creation of a coherent discourse. RH seems
to have a role in the comprehension of extended discourse, but deciphering the
meaning of words and sentences seems to take place primarily in the LH.
Speakers with right hemisphere lesions show more subtle deficits when tested.
Most severe impairments of spatial abilities occur more commonly following
damage to RH. There is a greater participation of RH during the comprehension
of signs. Areas included are Right Temporal areas, Right Posterior areas and
Right Superior Temporal Lobe. Right parietal cortex
was seen to be active to depict spatial scenes. While RH appears strongly tuned
towards semantic interpretation and global meaning; LH seems necessary for fine
aspects of on line sentence processing and literal meaning. Imaging results
have shown activation of Broca’s area : in hearing patients when they speak and
in deaf patients when they are signing. Signing activated left supramarginal
gyrus, which was not been greatly implicated in phonological retrieval for
spoken languages. Activation was seen in the left parietal cortex which was
similar to that seen in English speakers when they try to produce prepositions.
Various studies suggest different final organization of the brain system for
language in speakers and signers. The standard LH language areas may be
included to all natural languages but the final organization appears to be
determined by the exact language experience of the individual. The lesion
studies are making it clear that if differences exist between spoken and sign
languages, they are likely to be subtle and language specific. They share a
great deal of neural territory at the more central and higher level of brain
systems but diverge at the more peripheral levels of processing.
Study of Bilingual Brain
Some researchers believe that language
acquisition radically alters the brain through some kind of symmetry breaking
i.e. fixation of one of the possible values of each parameter, so that brain
ultimately get tuned to one language. Just consider the case of bilinguals (or
polyglots), what happen if acquisition of language L1 and L2 (different
languages) require different values for the same parameter.
Earlier there were hypotheses suggesting
that all languages known to a bilingual (or polyglots) are localized in the
same cerebral areas and that there is no basis for postulating a separate
cerebral organization for different languages in the bilingual’s brain. Then
came many hypotheses opposing earlier one which suggest, the brain areas
recruited for L1 learning and processing are different from those involved for
L2. Many studies supported the later hypothesis. One such study was mentioned
by Monika Ekiert. In this some patients showed Broca’s aphasia for L1 and
Wernicke’s aphasia for L2. A large series of recent studies led the researchers
to formulate the hypothesis that different languages are organized partly in
common areas and partly in specific and separate areas of the brain.
Stimulation in central region of Broca’s or Wernicke’s area tends to disrupt
functions of both the languages, but some areas’ stimulation disrupts only
either of the two. The difference in cerebral representation has been
attributed to a neural variability in the linguistic ability of individuals. The
anatomical separation of grammar and phonology in bilinguals varies according
to age and manner of language acquisition. In early bilinguals (who adopted L1
and L2 from childhood) no exhibition of different areas for different languages
was shown, while in late bilinguals (who adopted L2 in adult age) L1’s grammar
and phonology motor maps had developed a closed proximity and L2 developed in
separate area. Evans et al [2002]
found that for participants from a dual language environment, both early and
late acquisition of a second language resulted in a LH localization of L2.
Their data revealed increased RH involvement for later learned L2 in a single
language environment.
Illes,
Francis, Desmond (and many others) [1999] examined brain activation of
bilinguals of English and Spanish language users. The participants became
fluent in their L2’s (English or other way round) a decade after acquisition of
L1, but were proficient in both. They found that
the semantic activation for both the languages
occurred in the same cortical location. They inferred that learning a new
language, even after a decade, does not require the addition of a new semantic
processing system or the recruitment of a new cortical region. Such evidences
suggest a common cortical representation for L1 and L2 when levels of proficiency
in both languages are comparable.
CONCLUSION
Comparison of the views of co evolution
of language processing and brain has a two sided result. On one hand brain has
been shaped by and for language and has become “brain of the language”, and on
the other hand, language has changed to better suit communicative demands
offered by the users and learning acquisition of children and has become
“language of the brain”. Babies’ brain is primed to learn language and it does
this by making pathways and stronger connections, which may extend upto the age
of 10 years.
The two classical language areas,
Broca’s and Wernicke’s, are important brain areas for language processing but
many other LH and RHparts of the brain are involved in the task. The usage of these parts depend on language used,
task performed (name or recognize), conceptual category of items (unique,
common, familiar), modularity of input and output (spoken language or sign
language) and number of languages known to individual. For optimal retrieval of
words of different categories different anatomically separable regions are
involved, while for concept retrieval some regions are consistently associated.
This says partial segregation of different categories. The LH is found to be
dominant in language processing with many tasks affected by LH lesions. But
overall composition of language, in some sense, is distributed over the two
hemispheres. LH is generally related to fine aspects of sentence processing and
literal meaning and RH to visual spatial abilities. The standard LH areas may
be common to all natural languages but the final organization of language
system appears to be determined by the exact language experience of the
individual. In case of bilinguals the age of acquisition of language and
language environment seems to effect the language organization. Different brain
areas may be recruited for different languages. But when proficiency is kept
constant, age of acquisition doesn’t seem to have much effect.
From various studies and results
mentioned, it can be concluded that language is not a function restricted to
one hemisphere of the brain, but both the Left and the Right hemispheres have
their own vital role in language processing. When the parts of the two
hemispheres perform their respective tasks, some areas of brain take the charge
of leader and lead them to the completion of task successfully. The overall organization
of language in brain depends upon the individual and the proficiency and the
way he had acquired the language.
References
-Brain and language: A
perspective from sign language; Bavelier,
Corina and Neville.
-Building baby’s brain: Learning Language; web page.
-How does the Human Brain process
language? : New studies of deaf
and signers, hint at an answer: Hickok, Bellugi, Klima.
-Neural System behind word and
concept retrieval: H Damasio, Tranel,
Grabowski, Adolphs and A Damasio.
-Rethinking the Neurological
basis of Brain: Stowe, Haverkort
and Zwarts.
-The Bilingual
Brain; Monika Ekiert
-The co evolution of Language and
the Brain: A review of the contrastive views; Ken
Ramshoj Christensen.
-The Neural correlates of the
spatial language in English and American Sign Language: a PET study with hearing Bilinguals; Emmorey, Grabowski, McCullough, Ponto, Hichwa
and H Damasio.
-The Neural Systems underlying
language: Insights from sign language research;
Karen
Emmorey.
0 comments :