Language Development in Infants

Word Learning Lecture Notes

• Lecture Aims: Outline the mapping problem in word learning, describe children's early words (comprehension and production), and evaluate theories of early word learning.

Lecture Outline

• Why learning words is hard: Pointing and naming issues, the mapping problem.
• Early words: What do children know about their language, comprehension, and production.
• How children learn early words: Teaching words in the lab, some possible learning mechanisms (innate constraints, structural cues in language, social-pragmatic approach).

Word Learning is Hard (1)

• Word learning cannot be simply "point and name." Pointing and naming are not universal and usually only apply to nouns.

Word Learning is Hard (2)

• The mapping problem (Quine, 1960) - A word can refer to many different features of a concept.

Word Learning is Hard (3)

• Getting meaning right: Under-extension (using a word to mean only a certain thing)

Word Learning is Hard (4)

• Getting meaning right: Over-extension (using a word for more objects than it typically refers to).

Early Word Knowledge: Comprehension (1)

• Comprehension precedes production.
• 2-year-olds comprehend more words than they produce.
• Infants comprehend nouns earlier than verbs (e.g., 6 months old understand nouns).

Early Word Knowledge: Comprehension (2)

• Between 18 and 24 months, infants are faster at tasks related to comprehending words.
• By 18 months, full words are not necessary for comprehension.

Early Word Knowledge: Production (1)

• First words (around 12 months) are often nouns, verbs, action words, and adjectives.
• Children’s vocabularies increase greatly between 12 and 30 months. Often showing high variability.

Early Word Knowledge: Production (2)

• Early Noun Bias: Nouns predominate in early vocabularies.
• Natural partitions hypothesis: Early nouns refer to easily individuated concrete objects rather than states/actions.

Early Word Knowledge: Production (3)

• Socially Mediated Learning: Not all early words are nouns. Learning often occurs in situations where adults’ intentions are readily apparent irrespective of word class (e.g., hello, bye).

Early Word Knowledge: Production (4)

• Words used in diverse contexts (e.g., actions, naming objects, names for properties).

Early Word Knowledge: Production Errors (1)

• Under-extension: Words used only in a particular context or with specific exemplars. (Examples provided: "bye" only for putting down the receiver, "there" only for placing an object.)

Early Word Knowledge: Production Errors (3)

• Over-extension: Using a word beyond its true meaning. (E.g., calling a ball an apple)

Lecture Outline (2)

• Why learning words is hard.
• Pointing and naming issues.
• Early words.
• Teaching words.
• Some possible mechanisms of word learning: Innate constraints, structural cues, social-pragmatic approach.

Innate Constraints on Early Word Learning (1)

• Object constraint: Words refer to objects, explaining the early noun bias.
• Whole-object constraint: Words refer to whole objects, not parts. (Example: Gavagai = whole animal, not tail, ears, legs).

Innate Constraints on Early Word Learning (2)

• Principle of Contrast: No two words have identical meanings, helping overcome overextension.
• Mutual Exclusivity: Every object has only one name, helping overcome whole-object constraint.

Problems with Constraints Theories

• Do constraints explain word learning or merely describe it?
• Are constraints innate or learned?
• Are constraints specific to language?

Structural Cues to Word Meaning (1)

• Syntactic bootstrapping: Children use sentence structure to infer word meaning (examples of how a child may interpret what sib means).

Structural Cues to Word Meaning (2)

• Nouns refer to objects/categories and adjectives refer to properties.
• This difference influences how these words are used in sentences.

Structural Cues to Word Meaning (3)

• 4-year-olds pick different objects of the same kind when asked to find instances of a label but select a different object when asked to find another, different instance of that label.

Structural Cues to Word Meaning (4)

• 14-month-olds extend novel nouns and adjectives based on category (not property). Children seem to extend the noun to the category but not the property.

Structural Cues to Word Meaning (5)

• Category test: When children need to produce a blicket, they select a similar object.
• Property test: When required to produce something from the list in consideration to the colour it is, children have more difficulty as they select different objects at random.

Structural Cues to Word Meaning (6)

• With adjectives, children don't extend to the category or the property.
• When children are presented with a purple horse and a purple plate the children have more difficulty selecting the correct item based on the requested property.

Structural Cues to Word Meaning (7)

• Children usually select the same objects based on the colour when referring to a relevant property (e.g., are both purple).

Structural Cues to Word Meaning (8)

• Structural cues to nouns seemed to be learned earlier, unlike structural cues related to other words which were learned later.
• 18-month-olds show the same pattern as 21 month olds who are learning the language, but they are not yet great.

Structural Cues to Word Meaning: Verbs

• Structural cues help to further define verb meanings.
• 2-year-olds use structural cues to narrow down what they mean by a verb.

Structural Cues to Word Meaning: Issues

• Children are sensitive to sentence structure in some areas, but not clearly established what and when.
• Knowledge of words and broad categories is needed to understand sentence structure.

The Social-Pragmatic Approach

• Children learn words and meanings from pragmatic cues in the environment which remove ambiguities.
• Word learning is constrained by social world structures and social cognitive skills like joint attention and intention-reading.

The Social-Pragmatic Approach: Scaffolding and routines

• Children learn language from familiar routines and social contexts.
• Social routines, e.g., feeding, games, book-reading, help with learning.

The Social-Pragmatic Approach: Social-cognitive skills (1)

• Children use speaker’s intentions to infer word meanings and already know the name of the familiar object.
• This allows them to assume the speaker intends for them to refer to the novel object/referent.

The Social-Pragmatic Approach: Social-cognitive skills (2)

• Children use eye-gaze and joint attention to find the referent.
• 18-to 20-month olds are better at learning when the speaker and infant are both attending to the referent.

The Social-Pragmatic Approach: Intention Reading (1)

• Children infer meanings by looking at a speaker’s intentions.
• Children already know the name of the familiar object/referent.

The Social-Pragmatic Approach: Intention Reading (2)

• Children can differentiate intended actions from accidental ones when learning new verbs.

The Social-Pragmatic Approach: Issues

• What inferential skills do children bring to the task of word learning?
• Can this process account for complex syntax?

Word Learning Summary

• Language learning is not isolated but influenced by cognitive, social, and environmental factors.
• Comprehension precedes production, and early noun bias is a common pattern.
• Children access multiple sources of information when learning words.
• Different theories try to explain how children learn word meanings.

Critical Evaluations

• Unclear when different information is used across developmental stages.
• Would we expect the same strategies across languages and cultures?
• How do children learn less salient or more abstract words (e.g., the, happiness)?

Supplementary Information: Types of Studies

• Study what children already know about their language and when.
• How do children talk in naturalistic settings?
• Teaching children words in the lab and observing their word learning.

Supplementary Videos (1-4)

• Videos on child word learning in American Sign Language and other related contexts. A video on comprehension and production, early word learning, and joint attention and word learning.

References (1 & 2)

• Provides references on the topic from various papers relevant to the lecture. List of papers that were discussed in lectures on word learning.

This quiz explores key concepts related to language development in infants and toddlers, focusing on their ability to comprehend and produce words. It covers age milestones, theoretical approaches, and challenges faced during early word learning. Test your understanding of these important aspects of early childhood language acquisition.