Psychology Of Vocabulary Acquisition Research Paper

2. The Beginnings Of Word Learning

By the time children start to use words, they have already exercised many of their inborn capacities in the service of language learning. Research shows that sensitivity to sound and memory for sound begin even before birth, and that the capacities needed to segment the speech stream are in place early (see Hoff 2001 for details).

2.1 What Infants Bring To Word Learning

Recent advances in assessing the capacities of infants have revealed remarkable abilities that are recruited to the task of vocabulary acquisition (see Werker and Tees 1999). Newborn infants can detect minimal differences between sounds, and the differences they detect most easily are those occurring in the sound systems of the world’s languages. Newborns show remarkable sensitivity to the acoustic cues that specify word boundaries: they can discriminate between a two-syllable sequence extracted from a single word and such a sequence extracted from two separate words. Using acoustic cues, they also can discriminate the two basic kinds of words found in languages, i.e., content or ‘open class’ words like nouns and verbs and grammatical or ‘closed class’ words like prepositions and articles. Such sensitivities, plus an ability to keep track of statistical differences in the occurrence of different patterns of acoustic cues, enable infants by 8 months to segment a speech stream into words.

2.2 Experience And Development In Early Word Acquisition

During the first year, infants’ general capacity to discriminate speech sounds becomes more attuned to the sound system of the specific language in their environment. By 10–12 months, infants discriminate best the syllabic sound differences of their native language. Shortly thereafter, they begin associating sound strings with meaning, but at the same time their ability to distinguish between words on the basis of sound becomes more holistic and in some sense less discriminating. First word productions are different from later ones in that the first words often label whole scenes or events, or they are used to make requests; one 10-month old would call, ‘Dada mi(lk)’ from his crib when he wanted his morning bottle.

There are many similarities across children in the first 50 or so words produced: toddlers have an array of labels for common items and familiar people in their environment, along with words like ‘more,’ ‘up,’ and ‘all gone,’ that indicate changes of state and place. About half of all children appear to undergo a vocabulary spurt around 18 months of age, learning words at a rapid rate. Other children may show a more gradual increase in the rate of their word acquisition or experience a later spurt.

Nouns predominate over verbs in the early vocabularies of children learning English. This tendency toward early noun predominance was thought to be universal on cognitive grounds: relating sounds to real-world objects should be easier than grasping the relational nature of verb meanings (Gentner 1982). Although this may be true, which languages caregivers speak and what they, as members of their culture, find important to talk about also play a role in early vocabulary. For example, children learning Asian languages that typically place verbs in perceptually salient sentence-final positions tend to have a higher ratio of verbs to nouns in their early vocabularies than do children learning languages like English (Tardif 1996).

3. Working On Words

By 2 years of age, children typically are adept word learners, using just about everything they know to help them map sounds to meaning. Given how rapidly vocabulary grows even in the early years, it is hard to see how it could be otherwise.

3.1 Constraints On Word Meaning

Because in language meaning is arbitrarily related to sound, there are an infinite number of hypotheses learners could make about the meaning of any string of sounds they hear. Vocabulary would never be acquired if the learner had no way of constraining possible meanings. Researchers have proposed various constraints that can be thought of as learning strategies or default hypotheses that children use to make first guesses at the mappings between sound and meaning. One strategy suggested for infants is that they expect speakers to be talking about what they are looking at. Beliefs that a new label should refer to a whole object and not part of an object, that objects should have only one label, and that objects with the same label are alike in some fundamental way are examples of other suggested strategies for toddlers. Moreover, there is considerable evidence that preschoolers use what they know about language structure to inform their word learning (see Bloom 1994 and Gleitman and Landau 1994 for details and discussions of these sorts of constraints).

3.2 Vocabulary Organization

The evidence that children use information about language structure to help them acquire word knowledge is consistent with other data suggesting that children consider word–word relations and not just word–world relations as they acquire vocabulary. For example, even before they know what a particular color term means, or even which perceptual dimension the word color refers to, they regularly answer questions about the color of objects with color terms, albeit incorrect ones (Shatz and Backscheider 1999). They show similar behavior with letter and number-term categories. At least by the age of two, then, children are not just associating labels with objects or events, but they are relating words to one another, creating word categories based on common grammatical properties and on patterns of use in discourse.

3.3 Practice, Practice, Practice

The numerous reports of young children practicing their language skills (e.g., Kuczaj 1983) provide more evidence supporting the idea of early organization of word–word relations. One 20-month-old was observed reciting to himself a triad of antonym pairs, ‘in-out, up-down, hi-bye.’ At the age of 33 months, the same child, after talking to himself about family members’ possessions, spewed out a string of pronouns, ‘I, me, my, you, your, he, him, her, she, we, ours’ (Shatz 1994). Thus, throughout their early years, children reveal in their private speech that they think about various kinds of word-word relations.

4. Vocabulary Acquisition Later In Life

4.1 Sources Of Innovation

Vocabulary is the aspect of language that continues to show striking development beyond the early school years. This is because not only does an individual’s knowledge base grow, but there are many sources of vocabulary innovation in a speech community that an individual draws from throughout the life-span. New words or new meanings for old words are often introduced by groups such as adolescents eager to create a separate identity through language use, and the innovations often are adopted over time by the larger community. Other sources of vocabulary growth include borrowings from other languages, phrases used in public life or literature that take on idiomatic meaning and words created to describe new technologies. Little is known about how vocabulary grows throughout life, but it is likely that the patterns children display of partial knowledge about meaning organized along with facts about grammatical and discourse uses also characterize adult states of vocabulary knowledge as new words are acquired.

4.2 Vocabulary And The Brain

Although the rapid vocabulary growth of childhood undoubtedly slows over time, even seniors acquire new words, and vocabulary knowledge, like much linguistic knowledge, remains a robust skill among the elderly (Schum and Sivan 1997). Age-related difficulties in vocabulary use, such as word finding, word substitutions, and word loss can often be ascribed to particular brain insults like cerebral-vascular accidents resulting in area-specific brain damage. Others are likely related to decline in more general cognitive abilities like memory or speed-of-information processing (see Tun and Wingfield 1997). The occurrence of specific deficits for certain kinds of words (e.g., nouns) supports the view that words are indeed organized into a variety of categories, some of which are based on quite abstract characteristics.

5. Avenues Of Future Research

Future research will build on the discoveries of infants’ discrimination and segmentation abilities to address questions about the nature of early representations of sound-meaning relations. Why do children show decreased sensitivity to the specific sound characteristics of words just when they have recognized them as words? Why does a 2-year-old who has said ‘crain’ for train not register their own error but does so when an adult imitates ‘crain’? Other questions about early vocabulary acquisition concern the development of word understanding and use. Given that early vocabulary use reveals some organization based on word–word relations, how do children integrate information about word–world and word–word relations over time into comprehensive representations? Finally, future research must address important questions about the generality of the picture of vocabulary acquisition presented here. What is the relation between early and later vocabulary acquisitions? Can this view of vocabulary organization as one involving integrated aspects of sound, meaning, form, and use profitably be related to difficulties with word usage in aging or disordered populations? Second, can this account of vocabulary acquisition be appropriately applied to instances of acquisition in more agglutinative languages, i.e. those in which words themselves are made up of many more different pieces of meaning than they typically are in a language like English? The question of the generality of this account of vocabulary acquisition will undoubtedly require more than a one-word answer.

Bibliography:

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