Early Language Development

Clues to the Structure of the Human Mind

Prelinguistic communication

• Snow: infants and mothers engage in prelinguistic conversations– Mothers interpret the smiles and vocalizations of babies as social– culturally different: attributing intentionality to prelinguistic infants

• Cries and gurgles (when infants are not distressed)• Cooing: mostly vowel-like sounds or sequences of sounds• Babbling: 5-8 months: syllabic combinations of vowels and consonants

– allows practice with sounds before use them communicatively• Development of pointing

– 12 months point at object, then check adult’s focus of attention– 18 months check adult’s focus of attention, then point at object

Prelinguistic gestures• Gestures: actions and vocalizations which are

produced with deliberate intention to communicate, but which do not take the form of recognizable linguistic units– start around 8 months of age

• Bates et al.: 2 communicative/pragmatic acts (e.g., in pointing)– Proto-Declaratives (Assertions): the use of an object as

a means of obtaining adult attention– Proto-Imperatives (Requests): the use of adults as a

means to an object

Phonological development• Eimas et al., Jusczyk: infants as young as 4

months old can perceive phonemic distinctions

• Not only from the native language, but also from other languages– Categorical sound perception is innate

• but after 8 months or so: ability to distinguish nonnative contrasts diminishes– Phonological reorganization: phones are

organized into the phonemic categories of the native language

Early words

• Lexical development: the study of the development of vocabulary

• Semantic development: the study of the development of meaning

• the two are very much interlinked– what is the scope of meaning of early words?– how are prelinguistic meanings mapped onto

words?

Lexical development

• Clark: on the assumption that children start building their vocabulary at around 18 months, on average, 8-9 new words a day!

• Collected in diary studies and checklists that include words that the children are likely to acquire and that are filled out by parents– e.g., MacArthur Communicative Development

Inventory (MCDI)

What kinds of words are first words?

• Bates et al., Nelson: nearly 40-65% of child’s first 50 words are common nouns– verbs, adjectives, other words each account for

less than 10%• How about research in non-English languages?– Chinese and Korean children have as many or

more verbs in their early speech• Noun bias vs. verb bias languages

Cross-linguistic studies

• Tardif (Mandarin Chinese), Gopnik & Choi (Korean), Clancy, Fernald (Japanese)

• these languages are different than English– rich verbal morphology, verb-final, allow noun

ellipsis (i.e., dropping) where context is clear• Korean& Japanese-speaking mothers used

fewer nouns than English-speaking mothers• Korean and Japanese children use verbs earlier

than English-speaking children but use fewer and less varied nouns

Why a noun bias?• Why should nouns be acquired more rapidly than

other types of words?• The concepts referred to by nouns are clearer,

more concrete, and more readily identifiable than the concepts referred to by verbs– verbs are conceptually and linguistically more complex– Clark: early verbs tend to be general-purpose verbs

such do, make, go, and get

• Child-directed speech has a bigger range of nouns (i.e., object labels) than words for activities, properties, or relations

Noun bias: challenges

• Bloom, Gopnik: early words also include lots of relational words such as gone, up, there, more, uh-oh, again and social/performative words such as hi, bye

• cross-linguistic challenges-- e.g., Chinese and Korean

One-word utterances: ¨Holophrases¨

• one-word utterances are used with communicative intent• parents place interpretations on one-word sentences such as

up as ¨take me up¨• how can we attribute meaning to such brief and unstructured

utterances?– What are the communicative functions of these utterances? RICH

INTERPRETATION– researcher looks at nonverbal context to make rich interpretation

• Daddy– when pointing to a picture of daddy ==> NAMING– after finding daddy’s tie ==> POSSESSION– offering bottle to daddy ==> DATIVE, GOAL

• one-word utterances express underlying relational notions

Overextensions and Underextensions

• Unconventional word/meaning mappings• Overextension: when a child uses a word in a context

or manner that is inconsistent with, but in some way related to the adult meaning of the word– term is extended to concepts beyond the adult concept– daddy for adult men– cat for all four-legged animals– bye-bye to greet visitors

• Underextension: when a child uses a word for only a limited subset of the contexts used by the adult– cat for the home pet only– truck for the toy truck only

Semantic development: how?

• The gavagai problem: how do children map words onto observations about the world?– Infinite number of possibilities– how does the learner zero in to the right meaning?– has come to be known as the mapping problem

• Constraints or Principles– children entertain working hypotheses about the

meanings of new words– the meaning of new words involves some process

of comparing new to old semantic knowledge

Principles or constraints

• whole object constraint (Macnamara, Markman): when a new label is introduced, assume that it refers to the whole object rather than its parts

• novel name-nameless category principle (Golinkoff): new labels are mapped onto previously unnamed concepts

• principle of contrast (Clark): the principle that no two words have exactly the same meaning

• principle of mutual exclusivity (Markman): no overlap between words, assuming that an object can only have one name