Term paper
Islamic azad university of Bandar abas
The name of the course: Applied linguistics
Title: Neurocognitive linguistics
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Prepared by:M.A. H.mohammad sadeghi
Date: December 20, 2007
Contents
1 introduction
2 the human brain
2.1 nervous system
2.2 localization of language
3 neural learning and language acquisition
3.1 the human brain as self-organization network
3.2 critical age hypothesis
3.3 language acquisition
4 aphasia studies
4.1 broca’s aphasia
4.2 wernicke,s aphasia
4.3 conduction aphasia
5 conclusion
6 references
1 Introduction
In this paper, the author will present an overview of the field of neurolinguistics, which means the study of how the brain permits us to have language. The writer will analyze details of human language acquisition and show the relevance of the topic on some examples from the stores which stated.
In the beginning the author will give a short survey of the human brain function. It will lay the basic groundwork for the following explanation. Section 3 will give an introduction to neural learning and consider the significant aspects for language acquisition.
At last but not least, the author will look at the aphasia studies and evaluate stories and will illustrate explanations with relevant examples.
2 human brain
2.1 nervous system
The nervous systems of all animals have a number of basic function in common, most notably the control of movement and the analysis of sensation. What distinguishes the human brain is the variety of more specialized activities it is capable of learning. The preeminent example is language…..
The objects of study that must be linked in neurolinguistics are language and neural components. Approaches to neurolinguistic studies are the localization of speech relevant areas of human brain and to find out about the connection how these areas work together. Therefore in the following paragraphs the most important facts about the nervous system and the human brain will be reflected. These explanations are based on obler and gjirlow.
The human nervous system is composed of the central and the peripheral system. The peripheral nervous system is responsible for the regulation of vital body function such as breathing and temperature maintenance. For this reason it is also referred as automatic nervous system because it is functioning without our conscious awareness. The central nervous system consists of the brain and the spinal cord. Most crucial for neurolinguists is the brain itself, or more precisely, the outer surface of the cerebral hemispheres, the cortex. The center of human speech and language processing has been localized in the cortex. The fact that language is prevalently represented within the left hemisphere will be discussed below.
2.2 localization of language
2.2.1 the two sides of the brain
The human brain is split into two hemispheres. In the early part of the nineteenth century F. Gall and G. Spurzhim put forth theories of localization, holding that different human abilities and behaviors are traceable to specific part of the brain .the bases for some of their theories are amusing when looked at from our present states of knowledge. Gall, for example. Suggested that the frontal lobes of the brain were the location of language because when he was young he had noticed that the most articulate and intelligent of his fellow students had protruding eyes, which he believed overdeveloped brain material.
2.2.2 language within the left hemisphere
The human brain is split into two hemispheres. The left hemisphere controls any muscular activity on the right side of the human body and the right hemisphere operates vice versa. But how to localize the representation of brain centers for speech and language? This search dates back to the early nineteenth century. Some physician observed that brain injured patients with damage on the left hemisphere often lost speech or linguistic abilities.whil people with a lesion on the right side did not lose this ability.
From the vantage point of the present the dominance of the left hemisphere for language is largely uncontroversial. Today exist different test methods to prove the localization of language within the left hemisphere for most people. Resent studies estimate that 97 percent of the population has language represented in the left hemisphere.
3 neural learning and language acquisition
This section explains how the human brain is able to process and to store information, especially language relevant data like the meaning of words and and grammatical rules. This topic is also exceedingly interesting for computer scientists and closely related to artificial intelligence topics.
Considering linguistics topics, simulated neural networks are often used to represent grammatical rules in computers. They might even be the key to genuine synthetic speech, both understanding as well as producing.
3.1 the human brain as self –organization network
Neural learning in the brain can be realized on the one hand by changing the network structure, which will only take place in early childhood when new cell assemblies can be formed, and by changing the edge weighting on the other hand. The neural network in the human brain is formed by the genetic code acting as a framework, and by individual development. Long term- memory is either achieved by changes on the synapses (more strength connection) or by changes of functional units (new cell assemblies). A connection can become stronger when the same path is used often; the other way round a connection that is rarely used will weaken.
Its complexity also explains why the human brain still can be superior to current computer systems in solving different tasks. Computers are able to process lots of uniform data really fast, but they get in trouble with an increasingly complex input.
3.2 The critical age hypothesis
The development of lateralization in the brain may be connected to the language learning abilities of children, in that the “critical age” for first language acquisition coincides with the period when lateralization is taking place and ends when it is complete. The earliest hypothesis placed the end of lateralization at puberty, which appeared to be a crucial limit for ease of acquisition. More recently, however, it has been suggested that lateralization may be completed by the age of the five. Perhaps this is why so much of the grammar has already been acquired by the child at that age.
Language learning and lateralization may go hand in hand, but the relationship between the two is not clearly understood. We are not certain whether language is a prerequisite for for the development of lateralization or whether lateralization precedes language acquisition. In the attempt to understand the role of lateralization as it relates to critical age hypothesis, it is interesting to look at the development of bird songs and calls. From the point of view of human language research, the relationship between the innate and learned aspects of bird songs is significant. Apparently, the basic nature of the song of some species is biologically determined, but the details are learned, and can only be learned if exposure to the songs of their species occurs within a critical period.
3.2.1 critical period
The critical period in language acquisition which is the first language of a child must be acquired during a period between 18 month and early puberty to achieve proficient results. In reference to my explanations about neural learning I can accomplish this theory. In early childhood the brain has an initial plasticity where new cell assemblies can be formed easily. This ability will be lost later in life when brain structures become less flexible. The learning process is gradually displaced to changes on synapses than on creation of new functional units. First language learning will form the necessary structures in the brain to represent the lexicon and grammatical rules as well as the mental representation of symbolized words. Language relevant knowledge is stored in form of mental maps on a linguistic meta-level where similarly and synonymously used words or rules as stored in the same local areas.
In addition this also explains why there is a greater risk of permanent aphasia after a brain lesion as an adult. Whenever brain structures are damaged in early childhood the brain is much more flexible to compensate language deficits.
3.3 Language acquisition
The ultimate goals of children mastering their native language and adults studying a foreign language are often the same –to acquire knowledge of the language sufficiently rich and correct to result in fluent performance equivalent to that of adult native speakers. It is a well-known fact that all normal children, and many who have mental or physical abnormalities, succeed in achieving this goal without any formal teaching. In this sense, children acquire a language; they don’t learn it in the way that they learn geography. On the other hand, adults, even with the guidance of experienced teachers, often fail to achieve fluency in language. There is apparently a difference between native language acquisition and foreign language learning. These areas of investigation are by no means new. Educators and psychologists have been concerned with them for many years. But it is only recently that linguistic theory has become sufficiently well developed to provide a basic understanding of the nature of language and thereby a basic framework for investigation.
The learning and development of a person’s language. The learning of a native or first language is called first language acquisition, and of a second or foreign language, second language acquisition. Acquisition is often preferred to “learning” because the latter term is sometimes linked to a behaviorist theory of learning. Language acquisition is studied by linguists, psychologist and applied linguists to enable them to understand the processes used in learning a language, to help identify stages in the developmental process, and to give a better understanding of the nature of language.
3.4 the legend of Tarzan, lord of the apes
The legend of Tarzan, lord of the apes (1984) by Hugh Hudson is an adaption of Edgar Rice Burrough,s novel Tarzan of the apes. The linguistic significance of this story is based on the question whether a child that got lost in the jungle and was raised by up by apes far from any human contact can acquire language when he or she meets another human by chance at the age of twenty.
The story begins with two shipwrecked English nobles, the heir to the Earl of Greystoke and his pregnant wife, who ran ashore on the west cost of Africa. Their effort to survive in the hostile wilderness fails and ends tragedy. When they die; only their new born baby son is left. Alone in the jungle he gets adopted by an anthropoid ape that has lost her own baby. The baby, Tarzan, grows up with the apes and gets part of their community.
Despite the fact that he is far from any human contact Tarzan soon develops a growing consciousness for his difference. When he finds the wooden hut of his parents by accident he begins to realize that he is distinct from the apes. Tarzan with his given intelligence is able to use the knife to his advantage, although he has never seen anybody using it before, whereas the apes aren’t able to use it. That is why he is in the position to become the leader of the apes after the breathtaking fight with the ancestral group leader.
3.4.1 linguistic relevance
The crucial part of this story is when Tarzan eventually meets the Belgian explorer captain `D`arnot who gradually teaches him how to talk and realize that he is human. Regarding my explanation in the previous section I must come to the conclusion that it must be impossible to learn human language in Tarzan’s position. if he had been found at the age four or five it would have been possible to teach him language in the way it is stated in the story. Even then he would have to struggle with irreparable deficits in language learning similar to children suffering from speech disorder. Based on the fact that each neural network needs a training phase to gain it is experience it’s possible to draw the conclusion that human beings are only able to develop speech and language abilities when they hear other people speaking. The age is a really important aspect, from my point of view I would say that even the time before the first word is spoken in childhood is eminent. I suppose that grammatical structures are build in the brain before human are able to speak the first word themselves. When Tarzan has human contact at the age of twenty,
The development of linguistic structures in his brain was finished for a long time.
4 aphasia studies
4.1 broco’s aphasia
Paul broca, a French surgeon, reported in the 1860sthat damage to this specific part of the brain was related to extreme difficulty in producing speech. It was noted that damage to the corresponding area on the right hemisphere had no such effect. This finding was first used to argue that language ability must be located in the left hemisphere and since then has been taken as more specifically illustrating that broca,s area is crucially involved in the production of speech.
The type of serious language disorder known as broca,s aphasia(also called “motor aphasia’)is characterized by a substantially reduced amount of speech, distorted articulation and slow, often effortful speech.
4.2 wernica,s aphasia
Carel wernicke was a German doctor who, in the 1870s, reported that damage to this part of the brain was found among patients who had speech comprehension difficulties. This finding confirmed the left hemisphere location of language ability and led to the view that wernica,s area is part of the brain crucially involved in the understanding of speech.
The type of language disorder which results in difficulties in auditory comprehension is some times called ‘sensory aphasia’, but is more commonly known as wernicke,s aphasia.
Someone suffering from this disorder can actually produce very fluent speech which is, however, often difficult to make sense of very general terms are used, even in response to specific requests for information.
4.3 conduction aphasia
One other, much less common. Type of aphasia is identified with damage to the arcuate fasciculus and is called conduction aphasia. Individuals suffering from this disorder typically don’t have articulation problems. They are fluent, but may have disrupted rhythm because of pauses and hesitations.
Comprehension of spoken words is normally good.however, the task of repeating a word or phrase (spoken by someone else)will create major difficulty, with forms such as vaysse and fosh being reported as attempted repetitions of the words’base’and ‘wash’. What is heared and understood cant be transferred to the speech production area.
5 conclusion
In this paper I discussed important aspects of the connection between language and brain. I examined how language acquisition phenomena can be explained by neural network behavior and the relation between computer input and brain structures. In conclusion it can be noticed that the critical period in first language acquisition is based on neurological reasons. Apparently these reasons don’t effect second language acquisition that much. The Tarzan’s story gives evidence of the considered facts and provides an interesting and fascinating access to the topic.
6 references
Yule, G. (1996) The study of language (2nd edition) Cambridge University press. London.
Fromkin, v. & Rodman, R. (1988) An introduction to language (fourth edition) university of California, los angles.
Falk, j. (1978) Linguistics and language (2nd edition) Michigan state university, New York.
Richard, j., Platt, j. & Platt, H. (1992) Dictionary of language teaching &applied linguistics:London.
Lambert,W.E.(1974)Psychological approaches to the study of language.bellingham:western.
Gardner,R.C.(2003) motivation and second language acquisition.journal of psychology,34,21