Psycholinguistics is concerned with the relationship between language and the mind. This distinguishes it from sociolinguistics, on the one hand, where the focus is on the social dimension of language, and stylistics, on the other, where it is on the expressive functions of language. Psycholinguistics explores the psychological processes involved in using language. It asks how we store words and syntactic structures in the brain, what processes of memory are involved, and how we understand and produce speech. These are all of considerable practical importance when it comes to understanding language disorders. But above all, psycholinguists are interested in the acquisition of language: with how children learn.
Many linguists feel that if we can understand the internal mechanism which enables children to learn language so quickly we shall have penetrated one of the deepest secrets of the mind. To what extent are humans programmed from birth to acquire language? Is there such a thing as a language gene? Or is it simply that we have a general cognitive, or mental, ability that enables us to pick up language quickly? All of these issues are part of an ongoing debate within linguistics. Currently, the genetic view of language ability holds the field. Book by the psycholinguist Steven Pinker, entitled The Language Instinct (1995), makes a strong case for considering the elements of linguistic knowledge to be innate. This fits in very neatly with the Chomskyan concept of universal grammar: the idea that there is a common underlying structure to every language, the knowledge of which we are born with.
Psycholinguistics, then, is at the theoretical cutting edge of linguistics and, as such, is pretty heady stuff. So the question is, how can we begin studying it? First of all, we can be encouraged by the fact that much of the recent literature on the subject is very accessible. There is a strong tradition within linguistics of popularising the results of research in ways that demand little previous knowledge. The work of Pinker, mentioned above, and, in particular, Jean Aitchison, provide excellent ways into the subject. In these works one can find discussions of the various methods by which psycholinguists gather their evidence and how they set about analysing it. Secondly, as with sociolinguistics, one can carry out simple observational tasks oneself.
The most effective way to do this is to observe and monitor the speech of one or two young children over a period of time. You need to have in mind, of course, what you are looking for and the purpose of the activity. Your initial concern is to identify distinctive usages, either in sounds, syntax, or word meanings. You will be surprised in doing so how much of children’s speech you have hitherto taken for granted. The next stage is to establish what kind of rule your informants are following in producing these usages. Psycholinguistics proceeds on the principle that children’s use of language is rule-governed. You could start with observing how children form the plural and the past tense. These probably comprise the most conspicuous ‘errors’ in childhood speech. Young children will frequently say tooths and mouses, instead of teeth and mice, and holded and finded, instead of held and found. These are examples of over-generalisation the extension of a rule beyond its proper limits. In these cases the child knows the regular rule for forming the plural and the past tense but doesn’t know that these particular words are irregular. Having established the presence of this phenomenon, you can then test to see whether all irregular forms are regularised or only some, and how long it takes a child when corrected to acquire the correct form. It’s on the basis of experiments like these that psycholinguists form hypotheses about how children memorise forms and self-correct.
Over-generalisation is a frequent phenomenon in language development. It can be found not only in syntactic usage but also in word meanings. Many young children will sometimes refer to all animals as dogs or call all vehicles cars, and perhaps more disconcertingly, all men, dad. Discovering the limits of these words, what they do, and do not, apply to, is a useful way of penetrating the child’s semantic system. It can take time, for example, for children to learn that words can refer to separate things. When a child refers to milk, for instance, does s/he mean the whole process of pouring it into a mug and placing it down, or does it have the restricted meaning we are used to? Children also under-generalise; indeed, undergeneralisation is probably a more frequent phenomenon than its counterpart. A child may often only be able to use words in a particular context. It’s not uncommon for children to call their own shoes shoes but not know what someone else’s are called.
An initial way into psycholinguistics is to carry out some field research of your own into the acquisition of language, using a couple of basic concepts as your guides. On the basis of this, you can speculate about the kinds of lexical, syntactic, and semantic knowledge which your informants possess. If you do this it will enrich your understanding of the linguistic literature which you read. You will also find that it adds to your knowledge of how language changes; because all of us under- and over-generalise. Over-generalisation is one of the processes behind the loss of inflections from Anglo-Saxon times; we used to have many more irregular forms then than we do now. The morphology of modern English has developed as a consequence of generalising particular ways of forming the plural and past tense into regular paradigms. And it is also a key process in dialectal change. People who say I loves him are generalising the rule for the third person singular to cover all forms of the present tense. And in using a word like deer with its modern meaning we are under-generalising it: its Anglo-Saxon original, deor, meant an animal.
Having begun in a fairly simple way you can extend the process and consider more complex aspects of language acquisition: the formation of the negative, for instance. It takes some time for children to acquire the specific rule about attaching the negative to the auxiliary verb. Initially they will tend to put it at the beginning of the word string: no Jenny have it. Later the child decides to put the negative after the first noun phrase: cat no drink; he no throw it. The interesting thing about these rules is that the child cannot have acquired them from listening to adult discourse. They have been generated from scratch. And yet they are commonly followed by most children. Are they then a representation of some internal grammar in the child’s brain? Does the child start out with a set of possibilities for the formation of the negative and narrow them down as s/he encounters confirmation or disconfirmation from the speech of others? Questions like these form the basis of much psycholinguistic enquiry. It’s impossible to see directly into the brain so all we have is the second-hand evidence of language to work on. Over the years psycholinguists have amassed a good deal of observational data and case history analysis, all of which you can work through in time, but it is no substitute at the outset for making your own observations, and for using your linguistic knowledge to speculate about how we manage what is, arguably, the most amazing learning feat of our lives.