Language Acquisition PDF

Many people believe that language is what sets humans apart from other animals. Languages are highly complex and sophisticated systems. So how do we humans manage to learn such complicated systems? A predominant theory assumes that part of our ability to acquire language is innate and that children...

Many people believe that language is what sets humans apart from other animals. Languages are highly complex and sophisticated systems. So how do we humans manage to learn such complicated systems? A predominant theory assumes that part of our ability to acquire language is innate and that children learn language by “inventing” the rules specific to their language. When acquiring one or more native language(s), all children go through the same stages of language development: they start by babbling, then learn their first words, go through a so-called one-word stage (during which they can utter only one word at a time), enter the two-word stage, and finally learn the more complex structures of their language(s). Language acquisition is not limited to children; many people learn a second language later in life. However, second-language acquisition can differ from first- language acquisition in many respects. Contents 1. Theories of Language Acquisition Discusses the innateness hypothesis and introduces a number of theories of language acquisition. 2. First-Language Acquisition: The Acquisition of Speech Sounds and Phonology Describes how infants perceive and produce sounds, and discusses the acquisition of phonology, including babbling and first words. 3. First-Language Acquisition: The Acquisition of Morphology, Syntax, and Word Meaning Discusses the one-word stage, the two-word stage, and later stages of language acquisition, and introduces phenomena involved in the acquisition of word meaning. 1. Theories of Language Acquisition 1.1 About Language Acquisition Humans are not born talking. Instead, we typically learn to understand language and to speak during the first few years of our lives, before we even enter kindergarten or grade school. Language is a communication system consisting of sounds, morphemes, words, and rules for combining all of these. The knowledge of these elements enables people to understand and produce sentences they may never have heard or uttered before. So how does a child acquire this knowledge? If knowing a language were simply a matter of knowing a lot of words, language acquisition would just be a process of figuring out what the words were and memorizing them. Instead, children must acquire a grammar with all its components and rules. How do children learn these rules? For instance, how do they learn that the morpheme un- (meaning ‘not’) attaches to adjectives to form other adjectives having the opposite meanings? How do they learn to compose a sentence from a noun phrase and a verb phrase? Rules, unlike words, are never explicitly stated, so the child cannot just memorize them: he must somehow figure the rules out on his own—a remarkable intellectual feat. Various theories have arisen that attempt to account for how children acquire language. One theory that has found a lot of support throughout the years is that at least part of the human language ability is innate. We will first explore the innateness hypothesis and the evidence for it. However, innateness alone does not answer all of the questions about how children acquire the specific language that is spoken around them. Again, there are a number of theories that have been proposed for how additional, more specific knowledge is acquired. We will briefly consider two early ones, Imitation Theory and Reinforcement Theory, which have been refuted but which remain part of popular belief. It is therefore important to point out why these theories are inadequate. We will then consider three more current theories of language acquisition: the most influential of them is the Active Construction of a Grammar Theory. This theory is the one that most linguists believe today. However, there are a number of influential competing theories. Of these, we will introduce Connectionist Theories and Social Interaction Theory.  1.2 The Innateness Hypothesis A hypothesis underlying many theories of language acquisition asserts that language ability is innate in humans. That is, humans are genetically predisposed to acquire and use language (though not any particular language, of course). This theory claims that babies are born with the knowledge that languages have patterns and with the ability to seek out and identify those patterns. Some theorists have even claimed that humans have innate knowledge of some core characteristics common to all languages, such as the concepts of ‘noun’ and ‘verb.’ These basic features shared by all languages are called linguistic universals, and the theoretically inborn set of structural characteristics shared by all languages is known as universal grammar. No one knows exactly what the contents of universal grammar might be, though this is currently an active area of research in linguistics. The claim that linguistic ability is innate in humans is supported by, for example, the work of biologist Eric Lenneberg. He studied animal behaviour and developed a list of characteristics that are typical of innately determined behaviours. Innate behaviours are present in all normal individuals of a species, whereas learned behaviours are not. Walking, for instance, is a behaviour for which humans are genetically predisposed (that is, humans learn to walk as a natural part of development, without being explicitly taught), but playing the piano or riding a bicycle must be specifically taught. Is talking like walking, or is it like playing the piano? To answer this, let’s examine Lenneberg’s characteristics of biologically controlled behaviours. If language acquisition has each of these characteristics, we can safely assume that it is a genetically triggered behaviour. (1) Lenneberg’s characteristics of biologically controlled behaviours: 1. The behaviour emerges before it is necessary. 2. Its appearance is not the result of a conscious decision. 3. Its emergence is not triggered by external events (though the surrounding environment must be sufficiently “rich” for it to develop adequately). 4. Direct teaching and intensive practice have relatively little effect. 5. There is a regular sequence of “milestones” as the behaviour develops, and these can usually be correlated with age and other aspects of development. 6. There is likely to be a “critical period” for the acquisition of the behaviour. Lenneberg further proposes that innate behaviours have a critical period associated with their emergence. The term critical period describes a period of time in an individual’s life during which a behaviour—in this case language —must be acquired; that is, the acquisition will fail if it is attempted either before or after the critical period. The critical period for language acquisition is assumed to extend from birth to approximately the onset of puberty. During this time, a child needs exposure to language in order to develop the brain structures necessary for language acquisition. If a child is not exposed to language at all during this time, then the child will never acquire normal language skills and, in fact, may not acquire language skills at all. If a child has acquired a native language during the critical period and starts learning a second language before the age of twelve, the child will likely achieve native competence in this second language as well. However, if the second language is learned after about age twelve, the child is likely never to acquire complete native competence in the language. How can we tell whether there really is a critical period for first- language acquisition? To prove this, we would have to show that language skills could not be acquired normally or even at all if the learning began after the critical period had ended. This could be accomplished by depriving a child of linguistic input for the early years of life, but obviously it would be highly unethical to submit a child to such treatment. However, there are least two sources of information available to linguists that support the claims that there is a critical period for first-language acquisition. First, evidence for the critical period hypothesis comes from children who, owing to unfortunate circumstances, were exposed to little or no language during their early lives. These children were either neglected by their caretakers (neglected children) or grew up in the wild, often with animals (feral children). When these children were rescued or discovered, researchers attempted to help them acquire language. The success of these attempts depended largely on the age at which the children were discovered. We will consider two such cases, outlined below: Genie was found in 1970 when she was nearly fourteen years old. She had been abused and isolated since the age of twenty months. When first discovered, Genie was completely silent. Thereafter, her language acquisition was extremely slow, and although she did learn to speak, her speech was abnormal. She was able to memorize many vocabulary items, but her expressions were formulaic, as in what is X and give me X. She never learned grammar. Isabelle was discovered in 1937 at the age of six and a half. Her mother was deaf and could not speak. Isabelle’s grandfather had kept Isabelle and her mother isolated but had not otherwise mistreated them. Isabelle then began lessons at The Ohio State University, and although her progress was at first slow, it soon accelerated. In two years her intelligence and her language use were completely normal for a child her age. At first sight, the cases of Genie and Isabelle seem to provide good evidence for the critical period hypothesis: Genie, discovered after the supposed critical period was over, never learned language; Isabelle, discovered before the end of the period, did. But evidence from feral or neglected children is problematic. Such children are usually traumatized or are not socialized before they are rescued or found. So it is possible that it is not the lack of exposure to language but rather a larger trauma that prevents them from acquiring language properly. For example, Genie had been beaten by her father for making noises, so her difficulty with language could have had multiple causes. The case of Isabelle is problematic for the opposite reason: prior to being found, she was locked in a room with her mother, and although her mother could not speak, they developed a rudimentary personal gesture system to communicate. Thus, Isabelle did have some exposure to a communication system during the early years of her life. It is possible that Isabelle acquired language not because she was discovered at an earlier age than Genie, but because she had access to a rudimentary communication system. Likewise, it is possible that Genie didn’t learn language not because she was discovered at an older age than was Isabelle, but rather because she had been abused. Stronger evidence supporting both the innateness of language and the critical period hypothesis for first-language acquisition can be found in instances of deaf children and adults who were initially raised in environments without access to signed language input. One particularly illustrative example is the case of the deaf population of Nicaragua in the late twentieth century. At the end of the 1970s, following Nicaragua’s civil war, the country founded a new state school for the deaf. In the late 1970s and early 1980s, deaf children and adults were able to come together in a way that had not been possible earlier in the country’s history. Most children and adults arrived at the schools with idiosyncratic and rudimentary homesign gesture systems. Homesign gestures are communicative gestures (a form associated with a meaning) that are invented by deaf children and the people with whom they routinely interact in cases where a signed language is not made available. Homesigns may represent the names of individuals such as family members and the names of common activities (‘eat’) or common objects (‘house’) that are often referred to. However, a homesign system is not a language: it is an extremely limited lexicon without a grammar. Thus the students arrived at the school with backgrounds that involved social interactions and communication and that were normal in every way except that they did not include exposure to language. Soon, combining the homesigns that the students brought with them as well as some newly created signs, the children at the school created a pidgin (a type of simplified language) to communicate with each other. After the pidgin was created by the first students at the school, younger children came and were exposed to the pidgin. Without instruction, and based only on their exposure to the pidgin used by their older peers, these younger children created Idioma de Signos Nicaragense (ISN), which is a full-fledged language with a complex system of grammatical rules. The creation of ISN has been cited as evidence for the innateness of language, because within two or three generations of students, children created a new and complete language. Because they did not have exposure to any other linguistic system, all of the grammatical principles that were developed in ISN must have arisen through some innate ability in the children to create a complete grammatical system. However, those students who first came to the school as older children, and who had not acquired any linguistic communication system prior to the