LANGUAGE ACQUISITION

Human language is a remarkable symbolic means of communication that makes it possible for individuals to convey their thoughts and feelings to others. Although babies are born completely without language, by the time they are three or four years old, children have acquired thousands of vocabulary words, complex grammatical and sound systems, and the ability to speak appropriately in many different social situations. Although societies around the world differ in many ways, language is a universal phenomenon, and children around the world acquire their native language in very similar ways.

The Structure of Language

All human languages include a number of systematic features that the young learner must master. Languages are organized hierarchically and include a number of subsystems. The systems of language include phonology, morphology, the lexicon and semantics, syntax, pragmatics, and discourse. Children begin to acquire some aspects of their language during their first few months of life.

The phonology of a language is its sound system. This system includes all of the significant sounds that are used in the language, as well as the ways in which they can be combined to make acceptable-sounding new words. For example, a new cereal in English might be called "Crunchix," but not "Kshicrun," because acceptable English words cannot begin with "kshi." Across the world, languages use many hundreds of different sounds, from trills on the tongue to scrapes in the throat, but each language employs only a small subset of these possible sounds. The sounds that the speakers of a language regard as different from one another are its phonemes. In English, for example, people make slightly different "p" sounds in words such as pool, where the "p" is followed by a puff of air (aspiration), or in words such as spool, where there is no puff of air following the "p." English speakers perceive these as just one sound, the phoneme "p." In the Hindi language spoken in India, however, the "p" without the puff of air and the "p" with the puff of air are different phonemes. The Hindi language has words such as phal ("fruit") and pal ("moment") that differing only in that puff of air. Some languages have many more phonemes than others, but it is typical for a language to have about twenty-six consonant and nine vowel phonemes. In written English, the alphabet does not always represent the sounds of the language clearly or consistently, but in Spanish or Russian, the sounds of the language and the letters used to represent them correspond quite well.

The morphology of a language is a set of rules for word formation and variation. (The term "rules" is used to refer to the way things are regularly done in a language by speakers of that language, not to a set of formal regulations that are taught in school.) Morphemes are the smallest units in a language that carry definable meaning or grammatical function (the word "hat," or the plural ending "-s," for example.) Addition of a morpheme can change a word from singular to plural or indicate the tense of a verb. Other morphological rules allow one word to be changed into another word (e.g., "fit" into "unfit") or into another part of speech (e.g., "fit" into "fitness").

The lexicon and semantics of a language are its vocabulary words and the meanings that go with them. Speakers of a language have a remarkably large and complicated mental lexicon or dictionary. English-speaking adults can recognize more than 50,000 different words, and in common speech, they can come up with or produce anywhere from 20,000 to 50,000 of those words.

The syntax of a language includes the ways that words can be combined or rearranged in order to produce different kinds of utterances (e.g., questions, negatives, imperatives, and passives). Children soon learn to understand syntax—such as the difference between "The tiger chases the girl" and "The girl chases the tiger." In English syntax, meaning depends on word order. Typically, the first noun in a sentence is the subject, and the next is the object. Subjects are often followed by verbs. All sentences do not follow this pattern in English, however, and children must learn to interpret passives and other complex constructions. Complex syntax is not mastered until well into the school years.

Pragmatics is the appropriate use of language in various social situations. People all know how to talk in different ways, depending on the situation they are in, or the person they are addressing. People speak differently to babies, to informal acquaintances, and to people in authority, for example. If people are called into court, they do not say "Hi, sweetie" to the judge, although they might say this to their neighbor's little girl; people's knowledge of pragmatics leads to their choice of words and their interpretation of the language that they hear in social situations. Depending on their own roles, the person they are addressing, and the situation they are in, speakers vary their language according to a complex set of pragmatic conventions. Parents stress the importance of pragmatics when they teach very young children social routines, such as when to say "hello," "thank you," and "bye-bye."

Children must gain an understanding of how connected sentences are related to each other. In English, people must use a noun before a pronoun referring to the same thing can be used. Thus, "My dog ate it" is not a good way to begin a conversation with one's teacher, but saying "it" makes sense if the teacher has just asked where the student's homework is, since, in this case, the "it" refers to the homework. How to make a conversation or engage in other spoken or written activities that last longer than a single sentence requires knowledge of the discourse conventions of a language. After children enter school and begin to gain literacy skills, learning to use all of the discourse rules that are involved in expository writing is a particularly difficult task.

Stages of Language Acquisition

Understanding how children acquire language makes it possible to identify instances where they may not be developing language in an age-appropriate way, and may need intervention or remediation. It also allows people to know when immature-sounding language is part of normal language acquisition (such as when a two-year-old says "top" instead of "stop," since it is normal for a child of this age to simplify the pronunciation of consonant clusters). Knowing what stage of language development a child has reached also makes it possible for people to interpret what the child says and to tailor their own language so that communication is effective.

At birth, infants are prepared to learn any language. For example, an American baby adopted by an Inuit-speaking Eskimo family would grow up speaking fluent Inuktitut and have no trouble saying words such as qikturiaqtauniq ("mosquito bite"). However, even before their first birthdays, babies begin to lose the ability to hear the distinctions among phonemes in languages other than their own. By around the age of six months, babies have already begun to hear the sounds of their own language in the same way that adult speakers do, as Patricia Kuhl and her associates (1992) have shown in their research.

Human infants are intensely social; even in the first few days of life, they look into the eyes of their mothers and are sensitive to the emotional tone of the human voice. Long before they say their first words, babies begin to acquire the communicative skills that underlie language. As they get a little older they begin to take their turn in little "conversations" with their caregivers. The adult speaks, and the baby's turn can be something as simple as a sneeze or a burp. As they near their first birthday, many babies understand fifty or more words and can point out the right person when asked "Where's mommy?" They show that they are intentional communicators even before they begin to talk, by using gestures, by using consistent word-like sounds, and by becoming insistent when they are not understood.

As their communicative skills grow, the ability of infants to produce speech sounds also develops. They begin to babble, or play with sounds, midway through the first year. At first, babbling may consist of just a few sounds. Soon, the infant begins to babble repeated syllables, such as "dada" and "baba." A little later, many babies babble long sequences of syllables that resemble the sentences of their language. Communicative development in the first year has universal features and occurs in this way in all parts of the world, regardless of the degree of sophistication of the culture or complexity of the language being learned. First words emerge during the babbling stage and are produced by many infants at about the same age when they take their first steps, around their first birthday or a little later.

Once babies have begun to produce a few words, they begin to use them for a number of purposes. The earliest words children acquire refer to things in their immediate world that are important to them. They learn the names of their relatives (e.g., their mommy or daddy) and words referring to food, to games, toys, animals, body parts, and simple actions (e.g., eat, sit, up, down). Babies tend to learn the names of things that move or that they can act on (e.g., a mitten or ball) rather than something that is not related to their everyday activities (e.g., the sky or a floor). Early words represent different parts of speech, such as nouns, verbs, and adjectives, although nouns tend to make up the largest category. These words are also simple in terms of their pronunciation and generally not more than two syllables long. Infants use their single words in fairly complex ways. They may say "cookie," meaning "I want a cookie" or "that is a cookie" or "another cookie." In this one-word stage of language acquisition, children are restricted to the here-and-now. They do not talk about the future or the past.

Late in the second year, after they have acquired about fifty words, children begin to put the words together into little two-word sentences. Children's early two-word utterances also have universal characteristics. Children around the world are trying to get across very much the same kinds of ideas. They want to ask for more of something ("more cookie"), to reject something ("no sock"), to notice something ("hi, doggie!"), or point out that something has disappeared ("all-gone milk"). These early word combinations are called telegraphic utterances, because the child makes them without articles, prepositions, inflections, or other little grammatical words, and they sound like telegrams. The child can now say such things as "That kitty," meaning "That is a kitty," and "Mommy sock," meaning "Mommy's sock" or "Mommy, give me my sock" or "Mommy is putting on her sock." The telegraphic utterances become longer as the child gains language ability and becomes able to say even more things. Although the language of toddlers is similar across all languages during the telegraphic stage, what is acquired next depends on the structure of the language that the child is learning.

As the child's utterances grow longer, grammatical forms begin to appear. In English, children begin to add articles, prepositions, and inflections to their language. English-speaking children learn the articles "a" and "the," but in languages such as Chinese or Russian, which do not have articles, they learn other things. One remarkable discovery has been that children acquiring a given language follow essentially the same order of acquisition. As the vocabulary of young children continues to grow they gain a knowledge of morphology even before they enter kindergarten that allows them to make plurals or past tenses of words they have never before heard. In fact, when a young child says "mouses" instead of "mice," this is good evidence that the child is learning the regular forms of the language and knows how to make plurals, even if he or she has not yet learned the irregular forms. Almost all pre-school children produce regularized plurals and past tenses such as "gooses" and "ringed" as they acquire the systematic aspects of their language. By the time they enter school, children also know how to make all of the basic sentence types of their language, and they can use them in connected discourse.

Although the basics of the language are acquired in the first few years of life, there is much to be accomplished during the school years as well. By the age of six, children have acquired approximately fourteen thousand words, as the linguist Eve Clark (1993) points out in her book The Lexicon in Acquisition. As children grow older, the words that are related to each other become associated in the mental lexicon, so that a word such as "doctor" becomes linked to words such as "nurse," "hospital," and "stethoscope." This growing vocabulary is necessary for success in school.

School-age children begin to use language in a variety of new ways. Children develop pragmatic skills as they interact with others, and they learn how to use language appropriately in many different situations. Their language becomes decontextualized, in the sense that they can now talk about things that are not in their immediate environment (e.g., ancient history, events in other countries). Another new development is the ability to think about language itself, to know what a word is and even what their favorite words are. This new skill, called metalinguistic awareness (awareness of language), contributes to their ability to make jokes and riddles and to engage in other kinds of wordplay with their peers. It also helps them to acquire literacy skills. Learning to read and write are, of course, essential developments in the school years.

Although it is evident that the major aspects of language acquisition are complete by the time an individual has finished formal schooling, language skills continue to develop throughout the life span. Individuals are continually adding new vocabulary and learning new pragmatic and discourse skills.

Theories of Language Acquisition

Although many researchers have described what happens during the course of language development, there is much debate over just how children are able to acquire such a complex system in such a short time. Several major theories have attempted to explain the mechanisms of language acquisition:

Learning theory explanations of language development are based on the work of B. F. Skinner and other behaviorists, who view language as just one kind of human behavior that is learned. According to this theory, children learn to imitate adults, who also actively teach the children the language. For example, when babies begin to babble, adults reinforce or reward the babbling. A little later, the adults are thought to reward systematically the utterances that become closer and closer approximations of the target language until, eventually, children are speaking like the adults around them.

Many linguists, including Noam Chomsky and Steven Pinker, believe that the basic principles of language are innate, or present at birth, and that only human beings are capable of language. According to this view, adults' role in children's language development is minimal; all that is necessary is for the infant to be exposed to language. A built-in mechanism in the brain—referred to as a "language acquisition device" (LAD)—allows the child to develop language skills in a very short time without explicit teaching. These theorists believe that language is a unique and separate ability and that acquisition is possible only during a brief critical period during early childhood.

Jean Piaget was a major proponent of cognitive developmental theory. According to this theory, language is not a separate capacity; rather, it is just one facet of children's general intellectual ability. Cognitive theorists believe that infants use their senses and motor skills to begin to learn about the world—for example, that cats are furry and say "meow"—and that once they have gained such knowledge, they map words such as "kitty" onto the concepts that they have already attained.

Social interactionists, including Jerome Bruner and Catherine Snow, view language as a facet of communicative behavior that develops through interaction with other human beings. They agree that humans have special linguistic abilities that are not shared by other animals, but they hold that children acquire language in part through the help of others, rather than purely through their own mental activity. Thus, interaction, rather than exposure, is seen as necessary. These researchers have found that there are special ways of talking to young language learners the world over that are tailored or fine-tuned to children's cognitive and communicative needs. They believe that the clear and simple child-directed language that adults use helps children to figure out how language works.

Understanding Language Acquisition

All of the components of language are important for communication, and disruption at any level can lead to miscommunication or even failure to communicate. For example, an individual who has not correctly acquired the sound system will not be able to make important distinctions between similar-sounding words (e.g., the difference between "ship" and "sheep"). Morphology and syntax are needed to convey meaning. A rich, shared lexicon, or vocabulary, is needed in a complex society in order to make reference to people, places, and concepts. The pragmatic system is particularly important in communication because even slight misuses or inappropriate uses of pragmatics can have quite disastrous interpersonal results, particularly if pragmatic conventions that govern politeness are violated. Finally, everyone must learn how discourse works in order to communicate about any connected set of ideas or events. If people understand how language is structured, they gain insight into what the basic building blocks of messages are and into what may have gone awry when communication fails.

See also:Alphabets and Writing; Interpersonal Communication; Language and Communication; Language Structure; Sociolinguistics; Symbols.

Bibliography

Bruner, Jerome. (1983). Child's Talk: Learning to Use Language. New York: W. W. Norton.

Chomsky, Noam. (1965). Aspects of a Theory of Syntax.Cambridge, MA: MIT Press.

Clark, Eve. (1993). The Lexicon in Acquisition. New York: Cambridge University Press.

Gleason, Jean Berko, ed. (2000). The Development of Language. Boston: Allyn & Bacon.

Kuhl, Patricia K.; Williams, Karen A.; Lacerda, Francisco; Stevens, Kenneth; and Lindblom, Bjoern. (1992). "Linguistic Experience Alters Phonetic Perception in Infants by 6 Months of Age." Science 255 (5044):606-608.

Piaget, Jean. (1926). The Language and Thought of the Child. New York: Harcourt Brace Jovanovich.

Pinker, Steven. (1994). The Language Instinct: How the Mind Creates Language. New York: Morrow.

Skinner, Burrhus F. (1957). Verbal Behavior. Englewood Cliffs, NJ: Prentice-Hall.

Snow, Catherine E. (1989). "Understanding Social Interaction and Language Acquisition: Sentences Are Not Enough." In Interaction in Human Development, eds. Marc Bornstein and Jerome Bruner. Hillsdale, NJ: Lawrence Erlbaum.

Jean Berko Gleason

Elena Zaretsky