LEXICAL DEVELOPMENT – EXPLOSION OF WORDS

1. LEXICAL DEVELOPMENT – EXPLOSION OF WORDS

2. Key Concepts for Understanding • Mental Lexicon • Words • Nominal • Word spurt • Word biases • Constraints in word learning • Pragmatic principles in word learning • Whorfian hypothesis

3. Mental Lexicon: Lexical Knowledge in Adults • The phonological, grammatical and vocabulary knowledge of words adults have. • You have a phonological knowledge if you know how the word sounds, grammatical if you know how to use the word in combination with other words, and vocabulary or definition if you know what the word means.

4. Mental Lexicon: Lexical Knowledge in Adults • The study of lexical development is the study of the child’s acquisition of a mental lexicon.

5. WHAT IS A WORD?

6. Word/s • Words are symbols that can be used to refer to things, actions, properties of things, etc. • The relation between words and what they stand for is arbitrary. • The notion of reference is difficult to define, but it is crucial to discussions of lexical development.

7. Word/s • Reference involves words “standing for” their referents, not just “going with” their referents (Golinkoff, Mervis, and Hirsh-Pasek, 1994).

8. The Course of Early Lexical Development First Words May Be Context Bound • Children usually produce their first words sometime between 10 and 15 months of age (Benedict, 1979; Fenson et al., 1994; Huttenlocher & Smiley, 1987).

9. The Course of Early Lexical Development • The particular sounds of first words are not derived in any obvious way from the language the child is learning. • In contrast, first words are approximations of words in the target language, even if somewhat rough approximations.

10. The Course of Early Lexical Development • First words may be context bound, and the first words children use may be tied to particular contexts (Barrett, 1995). • At the age of 12 months, Martyn Barrett’s son Adam used the word duck only when he was hitting one of his toy yellow ducks off the edge of the bathtub (Barrett, 1986).

11. The Course of Early Lexical Development • Barrett’s son never said “duck” in other situations, and also never said “duck” referring to real ducks. • The interpretation was that Adam “had not yet learned that the word duck could be used to refer to either his toy ducks or real ducks. Instead, his behavior suggests that he had simply identified one particular event in the context of which it was appropriate for him to produce the word duck (Barrett, 1986, p. 40).

12. The Course of Early Lexical Development • Allison Bloom as reported by her mother, Lois Bloom, the well-known child language researcher, produced the word car at the age of 9 months, but she said “car” only when she was looking out her apartment window at cars on the street. • She did not say “car” when she saw a car close up or when she saw a picture of a car in a book.

13. The Course of Early Lexical Development • Children’s first words may always be parts of routines or language games (Caselli and colleagues, 1995). Such situation-specific (Bloom’s car) or function-specific (Barrett’s duck) understandings of word use are crucially different from adults’ mental representations of words as symbols that refer.

14. The Course of Early Lexical Development • At around 12 months of age, infants begin producing their first words in so-called holophrases with discourse-appropriate intonation and emotional tone of voice (Barrett, 1982; Ninio, 1992). • Infants use their holophrases (single-word utterances) to convey the same sorts of communicative intentions for which they use their gestures (Bates, Benigni, Bretherton, Camaioni, & Volterra, et al., 1979; Tomasello, 2008).

15. The Course of Early Lexical Development • Behrend (1990) suggested that context-bound words are merely responses elicited by particular environmental conditions; he termed these words prelexical.

16. The Course of Early Lexical Development First Words Can Also Be Referential • M. Harris, Barrett, Jones, and Brookes (1988) conducted a research analyzing the first 10 words produced by four children. • They categorized the first words into three groups: context-bound, contextually flexible nominals or names for things and not nominals though contextually flexible in their use.

18. The Course of Early Lexical Development Why are some words context-bound and others referential? • Limited experience produces limited understanding to children. • The mothers used their children’s first words in contexts other than the ones in which their children used them. • Some words get used before that common meaning has been inferred.

19. The Course of Early Lexical Development • Words that are at first context bound gradually become decontextualized (Barrett, 1986; Bates, Benigni, Bretherton, Camaioni, & Volterra, 1979; Dore, Franklin, Miller, & Ramer, 1976). • The description of the beginning of lexical development is one in which children start out with at least two kinds of lexical entries: situation-specific and adultlike.

20. The Course of Early Lexical Development Vocabulary Development from First Words to 50 Words • Most children add words to their vocabulary slowly at first but with increasing speed as they approach the achievement of a 50-word vocabulary.

22. The Course of Early Lexical Development • Children’s first words reflect their experiences. They know names for people, food, body parts, clothing, animals, and household items that are involved in children’s daily routines (Clark, 1979) • Verbs include labels for actions that are part of children’s routines (e.g., eat, drink, kiss, sing) and verbs with more general meanings that are frequent in children’s input (look, go, come, do) (Naigles & Hoff, 2006)

23. The Course of Early Lexical Development • This linguistic condition is called noun bias. Noun bias is a word-learning bias marked by a disproportionate number of count nouns in toddlers’ early vocabularies. • It is believed that noun bias is a universal linguistic phenomenon present in all young children across cultures and languages (Brown, 1973).

24. The Course of Early Lexical Development • The predominance of nouns is one feature of early vocabularies (Bates et al., 1994; Benedict, 1979; Dromi, 1987; Gentner, 1982; Gentner & Boroditsky, 2001; Goldin-Meadow, Seligman, & Gelman, 1976). • For English-speaking children with vocabularies between 20 and 50 words, fully 45 percent of their vocabulary consist of nouns with 3 percent for verbs (Caselli et al., 1995).

25. The Course of Early Lexical Development • Natural partitions hypothesis – the physical world makes obvious the things that take nouns as labels, whereas the meanings that verbs encode have to be figured out from hearing the verb in use.

26. The Course of Early Lexical Development • Relational Relativity Hypothesis – refers to linguistic work showing that noun meanings are more similar across languages than are verb meanings (Gentner, 1982; Gentner & Boroditsky, 2001).

27. The Course of Early Lexical Development • Children understand that certain kinds of nouns (i.e., count nouns) label objects at the very beginning of language acquisition. Children’s first words, then, are the words they first know how to link to meanings. (Waxman, 1994; Waxman & Lidz, 2006).

28. The Course of Early Lexical Development • The easiest words to learn through observation are concrete nouns. (Gillette, Gleitman, Gleitman & Lederer, 1999). • Children acquiring Korean, Japanese, and Mandarin (Chinese) show less of a noun bias than do children acquiring English (Fernald & Morikawa, 1993; A. Gopnik & Choi, 1995; Tardif, Gelman, & Xu, 1999).

29. The Course of Early Lexical Development • Under-extensions are word-learning errors that occur when a child uses a word in one context yet fails to use the same word in other appropriate contexts. Children use words in a more restricted fashion.

30. The Course of Early Lexical Development • Overextensions are word-learning errors that occur when a child uses a word to refer to terms outside its category. Children use their words more broadly than the meaning truly allows.

32. The Course of Early Lexical Development • Word spurt (or vocabulary spurt) refers to the increase of the word-learning rate occurring in the second year of life. • Word spurt is a myth (P. Bloom, 2000).

33. The Course of Early Lexical Development Proposals Explaining the Word Spurt • The onset of maturation of internal word-learning constraints occurs at 18 months (Behrend, 1990; Mervis & Bertrand, 1994). • Reaching the threshold of a 50-word vocabulary gives children a basis for figuring out principles of how the lexicon works (L.B. Smith, 1995, 2001). • Children achieve a “naming insight” at which point they realize that everything has a name (McShane, 1980).

34. The Course of Early Lexical Development • At 18 months, children come to understand that words refer not just to particular objects but to object categories (Nazzi and Bertoncini, 2003). • Children’s phonological abilities influence their very early vocabularies, raising the possibility that changes in the nature of children’s phonological systems contribute to the word spurt (Vihman, 1996)

35. The Course of Early Lexical Development • The critical underlying change comes from ongoing cognitive development (Vihman, 1996). • Children begin to show a cognitive understanding that objects can be grouped into categories about the same time that they become very good at learning object labels—which, after all, label object categories, not individual objects (A. Gopnik and Meltzoff, 1986).

36. The Course of Early Lexical Development • Word learning begins months before children speak their first words. Children as young as 5 months selectively respond to certain words (Mandel, Jusczyk, & Pisoni, 1995).

38. Individual Differences in Lexical Development • Words taught as labels and given explicit definitions may be more likely to be used referentially from the beginning than words the child picks up from context. • Differences among children in the number of context-bound words in their early lexicons may also reflect differences among children in their approaches to the language acquisition task.

39. Individual Differences in Lexical Development • Some children seem to be more analytic about language learning than others. • Children are risk takers (Peters, 1983; Richards, 1990). • Sociability

40. Individual Differences in Lexical Development • In Nelson’s (1973) study of lexical development of 18 children, she found that some children’s vocabularies had much larger percentages of nominals than others’ did. • Nelson labeled the children as referential or referential language style with more object labels in their vocabularies, and expressive or expressive language style with relatively fewer object labels and more personal/social words.

41. Individual Differences in Lexical Development Environmental Factors that Influence the Rate of Lexical Development • The effects of birth order are small and not always found, but when they are found, they consistently show that firstborn children have a slight advantage in vocabulary development over later-born children (Fenson et al., 1994; Hoff-Ginsberg, 1998; Pine, 1995).

42. Individual Differences in Lexical Development • The effects of socioeconomic status (SES) on vocabulary development are also small at the beginning of language development, but these effects grow larger over time and always show that children of more educated parents have larger vocabularies than children of less educated parents (Fenson et al., 1994; Hart & Risley, 1995; Hoff-Ginsberg, 1998; Zhang, Hin, Shen, Zhang, & Hoff, 2008)

43. Individual Difference in Lexical Development • Mothers who not only use words that are new to their children but who also say something about what the word means have children who build their vocabularies at faster rates. • Longer sentences are more likely to contain explicit information about word meaning, and longer sentences are more likely to contain other, syntactic clues to word meaning.

44. Individual Difference in Lexical Development Child Factors that Influence the Rate of Lexical Development • Some children develop the joint attention skills that mutual engagement requires at a younger age than others (Carpenter, Nagell, & Tomasello, 1998). • Children who are very outgoing may elicit more input, which, in turn, may support more rapid language development (Slomkowski, Nelson, Dunn, & Plomin, 1992).

45. Individual Difference in Lexical Development • Phonological memory is the ability to remember a sequence of unfamiliar sounds. • S.E. Gathercole and Baddeley (1989) tested the phonological memory skills and vocabulary of 100 children, first at the age of 4 and then a year later at age 5.

46. Individual Difference in Lexical Development • Children exposed to media, books, and other educational aids are more likely to have richer vocabularies than those who are not. • The sex difference is small and not always present, but several studies have shown girls to be more advanced in vocabulary development than boys (Bauer, Goldfield, & Reznick, 2002; Fenson et al., 1994; Zhang et al., 1981).

47. The Process of Word Learning • Word/Speech segmentation is a problem when a child must find the word boundaries or spaces. Examples: FATHER: Who wants some mango for dessert? CHILD: What’s a semmango? CHILD: I know why he’s called Don Quixote. It’s because he’s riding a donkey.

48. The Process of Word Learning • Word mapping is a problem, described by Willard Van Orman Quine (1960), as an infinite number of hypotheses about word meaning are logically possible given the data the child has.

49. The Process of Word Learning Lexical Constraints on Referent Mapping • The whole-object assumption is the child’s assumption that words refer to whole objects (Markman, 1996). • The mutual-exclusivity assumption is the assumption that different words refer to different kinds of things (Markman, 1996).

50. Heather Goldberg and Johanne Paradis University of Alberta and Martha Crago University of Montreal Lexical acquisition over time in minority first language children learning English as a second language