Psycholinguistics gives a comprehensive and viable understanding of human language development. The most famous psycholinguist theorist, Noam Chomsky, has argued convincingly that human children develop language abilities according to a predetermined universal deep structure or grammar. The psycholinguistic approach provides invaluable tools for teaching children to read, write, and speak.
The development of language in the human child is certainly one the most astounding and impressive human accomplishments. A child must learn over ten new words each day, from the time they start speaking, in order to reach the average six-year-old vocabulary of 14,000 words (McConnell). Language allows humans to think and reason, and communicate with each other. It is an absolutely essential skill, not only in the complete development of the individual, but for the survival of the human species as a whole.
Psycholinguistics simply deals with the mental aspects of language acquisition, storage, production and comprehension. It has roots in both linguistics and psychology. Linguists generally study psycholinguistics through observations of spontaneous speech. In contrast, psychologists study psycholinguistics under controlled experimental conditions. The word psycholinguistics originated in the 1930's and is derived from a combination of three roots: the Greek psych (mind), Latin lingua (tongue), and -istics as in statistics (Xrefer).
Psycholingistics is a subfield within the wider study of language and communication, which includes non-verbal communication. Neurolinguistics is closely related to psycholinguistics, but focuses much more closely on the biological study of language and the brain (Kess).
Psycholinguistics has a relatively long history. Charles Darwin discussed language acquisition briefly in Mind. The first psycholinguistic experiments were conducted by British Psychologist Francis Galton, in his investigations of word association (McGroarty).
Modern psycholinguistics emerged in the mid-1960s with the work of Nam Chomsky. Chomsky argued that language likely had a genetic component, since all human languages all follow some rules of grammar and syntax. His work resulted in a flurry of subsequent research that was intent on determining if his theory of transformational-generative grammar had a solid basis in the real-life way humans stored and processed language. Early research to show Chomsky's theories in real-world situations, including child language acquisition had disappointing initial results. Chomsky continued to revise his theories, leading many leading psychologists to become frustrated with linguistic theory. As a continuing legacy, the psycholinguistics field is still fragmented (McGroarty; Kess).
Prior to the development of psycholinguistics, language acquisition was largely explained by a process of imitation production, comprehension, and the acquisition of language. Chomsky's theory of language is very different from those of behaviorists like B.F. Skinner. Skinner argued that the genetic component of language development comes is seen in the child's ability to learn. Skinner believed that language was learned through imitation, and positive reinforcement. In contrast, Chomsky argued the "naturist" position, that there is a universal deep structure or grammar that underlies all human languages. As such, children are born with the innate knowledge of rules and syntax (McConnell).
In Skinner's "imitative" approach, the child was believed to imitate the language of those surrounding him or her, and from this process of imitation somehow divined the rules of language.
Interestingly, the imitative approach explains quite well the selective reinforcement that parents use to shape their children's word usage and sounds when the children are babbling. However, the theory does not explain why all children go through a stage of babbling (McConnell). Another flaw in the "imitative" approach is the fact that children hear large numbers of ungrammatical sentences in everyday language, and yet manage to induce the correct rules of grammar. Further, children learn the rules of language very early, despite never directly hearing these. In addition, young children often hear grammatical speech, and yet create rules that are incorrect but remarkably consistent. For example, children often hear that the plural of moose is moose, and the plural of goose is geese, and yet consistently (at least at a limited stage of development) refer to the plural of moose as mooses, and the plural of goose as gooses (Taylor).
In contrast the unsuccessful "imitation" approach, psycholinguistics has made astounding and unparalleled progress in understanding child language acquisition. Regardless of the type of language, children worldwide show a remarkable similarity in how they acquire language. The development of language appears to be "hard-wired" or preprogrammed within the brain. Language development appears at a certain, specific point in a child's development, across culture and language systems, if the child is normal and unimpaired (Weaver).
Fascinatingly, child language has its own grammatical and syntactical rules. In other words, it is not simply an inferior form of adult language, but has its own structure and rules. Further, the rules of child language are strikingly similar regardless of the mother language of the culture. Certainly, these findings lend considerable credence to Chomsky's assertions that language acquisition has a genetic component. Researchers continue to attempt to discern how children move from this "child language" to more adult grammatical structures. For example, researchers continue to attempt to determine how children move from the child-based form "What kitty can eat?" To an adult structure of "What can kitty eat?" (Xrefer).
Certainly, there are various theories of language acquisition, of which Chomsky's is simply one of the most notable. Chomsky argued that children have an innate language acquisition device. This device was simply a set of set principles governing the structure of language, and a method of discovering other principles. In contrast, Piaget argued that relating language acquisition to underlying intellectual and cognitive development was crucial in understanding language acquisition. Other researchers felt that language acquisition was deeply rooted in the child's analysis of adult language. Many divergent theories seem to have some credence, thus it is importance to acknowledge Chomsky's important contribution, but to also realize that other theories hold some important keys to language learning (Taylor; Kess).
Despite their differences, the divergent camps in the field of language acquisition all note that language acquisition are roughly similar between all children. For example, most children begin to babble at about three to seven months, utter their first word at about six to twelve months. Children understand simple sentences at about eight to eighteen months, and speak two-word sentences at around sixteen to twenty months. Children generally speak full sentences by the age of two (McConnell).
Human language acquisition is believed to have four main aspects: phonemes, semantics, syntax, and pragmatics. Phonemes are the smallest units of language, including basic sounds like "ba" or "da." Semantics refers to the meanings of words. Syntax is the rules that allow words to be connected, making up the structure of language. Pragmatics refers to the socially appropriate use of speech (McConnell).
This existence of this age-dependent critical period further argues for a genetic basis for the abstraction of grammar and language rules that Chomsky advocated. From the ages of 2-7, human children appear to have a "critical period" of language learning. If children do not hear any language during this time, they will fail to develop normal language abilities. Two real-world examples illustrate the importance of the critical period on language development. In both cases, children were denied human language until after the critical period, and failed miserably in any attempts to teach language.
Victor, or the Wild Boy of Aveyron, was discovered roaming the forest near Aveyron in Southern France in 1799. The boy acted like a wild animal, eating off the floor, barking and growing like a dog, and despising clothing and baths. At the time of his discovery, Victor could not speak. He was taken in by Dr. Jean Marc Itard, a noted professional who taught the deaf to speak. Despite continued efforts, Victor never learned to speak more than a few of the most basic units of speech, and never learned even simple words (Kolb and Whishaw).