theories about how language works in the human mind attempt to account for, among other things, how we associate meaning with the sounds (or signs) of language and how we use syntax—that is, how we manage to put words in the proper order to produce and understand the strings of words we call "sentences". The first of these items—associating sound with meaning—is the least controversial and is generally held to be an area in which animal and human communication have at least some things in common (See animal communication). Syntax, on the other hand, is controversial, and is the focus of the discussion that follows.
There are essentially two schools of thought as to how we manage to create syntactic sentences: (1) syntax is an evolutionary product of increased human intelligence over time and social factors that encouraged the development of spoken language; (2) language exists because humans possess an innate ability, an access to what has been called a "universal grammar". This view holds that the human ability for syntax is "hard-wired" in the brain. This view claims, for example, that complex syntactic features such as recursion are beyond even the potential abilities of the most intelligent and social non-humans. (Recursion includes the use of relative pronouns to refer back to earlier parts of a sentence ("The girl whose car is blocking my view of the tree that I planted last year is my friend.")) The innate view claims that the ability to use syntax like that would not exist without an innate concept that contains the underpinnings for the grammatical rules that produce recursion. Children acquiring a language, thus, have a vast search space to explore among possible human grammars, settling, logically, on the language(s) spoken or signed in their own community of speakers. Such syntax is, according to the second point of view, what defines human language and makes it different from even the most sophisticated forms of animal communication.
Language acquisition, the process of learning a native or a second language. The acquisition of native languages is studied primarily by developmental psychologists and psycholinguists. Although how children learn to speak is not perfectly understood, most explanations involve both the observation that children copy what they hear and the inference that human beings have a natural aptitude for understanding grammar. While children usually learn the sounds and vocabulary of their native language through imitation, grammar is seldom taught to them explicitly; that they nonetheless rapidly acquire the ability to speak grammatically supports the theory advanced by Noam Chomsky and other proponents of transformational grammar. According to this view, children are able to learn the "superficial" grammar of a particular language because all intelligible languages are founded on a "deep structure" of grammatical rules that are universal and that correspond to an innate capacity of the human brain. Stages in the acquisition of a native language can be measured by the increasing complexity and originality of a child's utterances. Children at first may overgeneralize grammatical rules and say, for example, goed (meaning went), a form they are unlikely to have heard, suggesting that they have intuited or deduced complex grammatical rules (here, how to conjugate regular verbs) and failed only to learn exceptions that cannot be predicted from a knowledge of the grammar alone. The acquisition of second or foreign languages is studied primarily by applied linguists. People learning a second language pass through some of the same stages, including overgeneralization, as do children learning their native language. However, people rarely become as fluent in a second language as in their native tongue. Some linguists see the earliest years of childhood as a critical period, after which the brain loses much of its facility for assimilating new languages. Most traditional methods for learning a second language involve some systematic approach to the analysis and comprehension of grammar as well as to the memorization of vocabulary. The cognitive approach, increasingly favored by experts in language acquisition, emphasizes extemporaneous conversation, immersion, and other techniques intended to simulate the environment in which most people acquire their native language as children.
William James (1890) described the world of the newborn as a "blooming, buzzing confusion." It is now known, however, that, on the auditory level at least, the newborn's world is remarkably well structured. The cochlea (in the inner ear) and the auditory nerve (which connects the inner ear with the brain) provide extensive preprocessing of signals for pitch and intensity. In the 1970s and 1980s, researchers discovered that human infants were specifically adapted at birth to perceive contrasts in sounds such as that between /p/and /b/, as in the words pit and bit. Subsequent research showed that even chinchillas are capable of making this distinction. This suggests that much of the basic structure of the infant's auditory world can be attributed to fundamental processes in the mammalian ear. Moreover, there is evidence that some of these early perceptual abilities are lost as the infant begins to acquire the distinctions actually used by the native language. Beyond this basic level of auditory processing, it appears that infants have a remarkable capacity to record and store sequences of auditory events. It is as if the infant has a tape recorder in the brain's auditory cortex that records input sounds, replays them, and accustoms the ear to their patterns.
Children tend to produce their first words sometime between nine and twelve months. One-year-olds have about 5 words in their vocabulary on average, although individual children may have none or as many as thirty; by two years of age, average vocabulary size is more than 150 words, with a range among individual children from as few as 10 to as many as 450 words. Children possess a vocabulary of about 14,000 words by six years of age; adults have an estimated average of 40,000 words in their working vocabulary at age forty. In order to achieve such a vocabulary, a child must learn to say at least a few new words each day from birth.
One of the best predictors of a child's vocabulary development is the amount and diversity of input the child receives. Researchers have found that verbal input can be as great as three times more available in educated families than in less educated families. These facts have led educators to suspect that basic and pervasive differences in the level of social support for language learning lie at the root of many learning problems in the later school years. Social interaction (quality of attachment; parent responsiveness, involvement, sensitivity, and control style) and general intellectual climate (providing enriching toys, reading books, encouraging attention to surroundings) predict developing language competence in children as well. Relatively uneducated and economically disadvantaged mothers talk less frequently to their children compared with more educated and affluent mothers, and correspondingly, children of less educated and less affluent mothers produce less speech. Socioeconomic status relates to both child vocabulary and to maternal vocabulary. Middle-class mothers expose their children to a richer vocabulary, with longer sentences and a greater number of word roots.
Whereas vocabulary development is marked by spectacular individual variation, the development of grammatical and syntactic skills is highly stable across children. Children's early one-word utterances do not yet trigger the need for syntactic patterns, because they are still only one-word long. By the middle of the second year, when children's vocabularies grow to between 50 and 100 words, they begin to combine words in what has been termed "telegraphic speech." Utterances typical of this period include forms such as "where Mommy," "my shoe," "dolly chair," and "allgone banana."
At this same time, children are busy learning to adjust their language to suit their audience and the situation. Learning the pragmatic social skills related to language is an ongoing process. Parents go to great efforts to teach their children to say "please" and "thank you" when needed, to be deferential in speaking to adults, to remember to issue an appropriate greeting when they meet someone, and not to interrupt when others are speaking. Children fine-tune their language skills to maintain conversations, tell stories, ask or argue for favors, or tattle on their classmates. Early on, they also begin to acquire the metalinguistic skills involved in thinking and making judgments about language.
As children move on to higher stages of language development and the acquisition of literacy, they depend increasingly on broader social institutions. They depend on Sunday school teachers for knowledge about Biblical language, prophets, and the geography of the Holy Land. They attend to science teachers to gain vocabulary and understandings about friction, molecular structures, the circulatory system, and DNA. They rely on peers to understand the language of the streets, verbal dueling, and the use of language for courtship. They rely on the media for role models, fantasies, and stereotypes. When they enter the workplace, they will rely on their coworkers to develop a literate understanding of work procedures, union rules, and methods for furthering their status. By reading to their children, telling stories, and engaging in supportive dialogs, parents set the stage for their children's entry into the world of literature and schooling. Here, again, the parent and teacher must teach by displaying examples of the execution and generation of a wide variety of detailed literate practices, ranging from learning to write through outlines to taking notes in lectures.
Special Gift or Emergence?
Having briefly covered the methods used to study language acquisition and the basic phases in development, it is now possible to return to this question: Is language development best characterized as the use of a "special gift" or as an emergent result of various cognitive, neural, physiological, and social pressures? There are good arguments in favor of each position.
The special gift position views language as an instinct. People are often overpowered by the "urge to speak." Young children must feel this urge when they interact with others and have not yet learned how to use words correctly. It is important to recognize, however, that crickets, birds, snakes, and many other species can be possessed by a similar urge to produce audible chirps, songs, and rattling. In themselves, these urges do not amount to a special gift for language learning. Better evidence for the special gift comes from the study of children who have been cut off from communication by cruel parents, ancient Pharaohs, or accidents of nature. The special gift position holds that, if the special gift for language is not exercised by some early age, perhaps six or seven, it will be lost forever. None of the isolation experiments that have been conducted, however, can be viewed as providing good evidence for this claim. In many cases, the children are isolated because they are brain-injured. In other cases, the isolation itself produces brain injury. In a few cases, children as old as six to eight years of age have successfully acquired language even after isolation. Thus, the most that can be concluded from these experiments is that it is unlikely that the special gift expires before age eight.
The second form of evidence in favor of the notion of a special gift comes from the observation that children are able to learn some grammatical structures without apparent guidance from the input. The argumentation involved here is sometimes rather subtle. For example, Chomsky noted that children would never produce "Is the boy who next in line is tall?" as a question deriving from the sentence "The boy who is next in line is tall." Instead, they will inevitably produce the question as, "Is the boy who is next in line tall?" That children always know which of the forms of the verb is to move to the front of the sentence, even without ever having heard such a sentence from their parents, indicates to Chomsky that language must be a special gift.
Although the details of Chomsky's argument are controversial, his basic insight here seems solid. There are some aspects of language that seem so fundamental that humans hardly need to learn them. Nevertheless, the specific structures examined by linguistic theory involve only a small set of core grammatical features. When looking more generally at the full shape of the systems of lexicon, phonology, pragmatics, and discourse, much greater individual variation in terms of overall language proficiency appears.
To explain these differences, it is necessary to view language learning as emerging from multiple sources of support. One source of support is the universal concept all humans have about what language can be. A second source of support is input from parents and peers. This input is most effective when it directly elaborates or expands on things the child has already said. For example, if the child says "Mommy go store," the parent can expand the child's production by saying "Yes, Mommy is going to the store." From expansions of this type, children can learn a wide variety of grammatical and lexical patterns. A third source of support is the brain itself. Through elaborate connections among auditory, vocal, relational, and memory areas, humans are able to store linguistic patterns and experiences for later processing. A fourth source of support are the generalizations that people produce when they systematize and extend language patterns. Recognizing that English verbs tend to produce their past tense by adding the suffix -ed, children can produce over-generalizations such as "goed" or "runned." Although these overgeneralizations are errors, they represent the productive use of linguistic creativity.
Individual children will vary markedly in the extent to which they can rely on these additional sources of support. Children of immigrant families will be forced to acquire the language of the new country not from their parents, but from others. Children with hearing impairments or the temporary impairments brought on by otitis media (ear infections) will have relatively less support for language learning from clear auditory input. Blind children will have good auditory support but relatively less support from visual cues. Children with differing patterns of brain lesions may have preserved auditory abilities, but impaired ability to control speech. Alternatively, other children will have only a few minor impairments to their short-term memory that affect the learning of new words.
Because language is based on such a wide variety of alternative cognitive skills, children can often compensate for deficits in one area by emphasizing their skills in another area. The case of Helen Keller is perhaps the best such example of compensation. Although Keller had lost both her hearing and her vision, she was able to learn words by observing how her guardian traced out patterns of letters in her hand. In this way, even when some of the normal supports are removed, children can still learn language. The basic uses of language are heavily over-determined by this rich system of multiple supports. As a child moves away from the basic uses of language into the more refined areas of literacy and specific genres, progress can slow. In these later periods, language is still supported by multiple sources, but each of the supports grows weaker, and progress toward the full competency required in the modern workplace is less inevitable.
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