Traxler (2011). Chapter 9 Language Development in Infancy and Early Childhood.

Language Development in Infancy and Early Childhood

• Most children learn the language spoken by parents/peers without direct instruction, threat, or reward.

• Children can face challenges with pronunciation and may require speech therapy but generally acquire language skills barring genetic defects (like Down Syndrome).

• This chapter explores the challenges children face in mastering language and outlines studies indicating strategies used for language acquisition.

Prenatal Learning

• Classical Behaviorism: Children as a blank slate (e.g., Skinner).

• Newer research suggests infants have innate understanding of aspects like visual perception, object properties, and numbers.

  • Hypothesis: Babies Are Smart.

• Nativist Approaches: Language abilities as products of natural selection. Babies possess innate learning mechanisms to deduce adult language without knowing a specific language.

• Prenatal Learning Mechanisms:

  • Infants recognize their native language's prosodic features in utero.

  • The prenatal auditory system processes sounds from the environment beginning in the third trimester, particularly their mother's voice.

Evidence of Prenatal Learning

• Infants show preferences for their mother's voice and native language postnatally.

• The High-Amplitude Sucking (HAS) method tests infants' responses to familiarized stimuli before birth, indicating prenatal learning.

  • Research shows newborns prefer familiar stories read during pregnancy.

Infant Perception and Categorization of Phonemes

• Infants must learn speech sound inventories, word meanings, and sentence structure without direct teaching.

• Infants exhibit Categorical Perception similar to adults, perceiving phonemes as part of discrete categories.

• Phonemes: Basic sound units in language; infants learn to categorize these sounds through exposure.

Studies of Phonology

• Experiments show young infants (1-4 months) use the voice onset time (VOT) to discriminate phonemes.

• Infants maintain perceptual abilities for phonological contrasts, even without prior exposure, aiding in language learning.

• Infants lose the ability to distinguish non-native phonetic distinctions by about one year of age.

Solving the Segmentation Problem

• The challenge: Identifying where words begin and end in fluent speech.

• Experiments reveal that infants rely on various cues to segment speech, including:

  • Prosodic Characteristics: Stress patterns show potential word boundaries.

  • Statistical Learning: Infants notice the statistical probabilities of phoneme combinations, which helps them identify word boundaries.

Learning Word Meanings

• Word Learning Process: Children rely on context, joint attention, and their developing cognitive skills to discern word meanings.

• Various principles aid in learning, including:

  • Point-and-Say Technique: Associating words with their respective objects through labeling.

  • Poverty of the Stimulus and Conceptual Knowledge: Children infer meanings despite incomplete contextual clues through innate biases (whole-object bias).

Morphological and Syntactic Knowledge Acquisition

• After age 2, children start combining words into phrases.

• Key areas of focus include:

  • Word Categories: Understanding different word types.

  • Morphology: Learning how to modify words to convey tense, plurality, etc.

  • Phrase Structure: Comprehending how to combine words meaningfully.

Nativist vs. Probabilistic Learning Theories

• Nativist Theories (e.g., Chomsky): Suggest innate grammatical structures guide language development.

• Probabilistic Learning Theories: Indicate children learn gradually, adapting their language understanding based on frequent patterns observed in their environment.

Acquisition of Word Category Knowledge

• Children make use of semantic bootstrapping, using their knowledge of physical categories to map onto linguistic categories.

Morphological Acquisition of Past Tense

• Young children memorize past tense forms but may also apply rules learned from common patterns in language—leading to errors through over-regularization (e.g., "thinked" instead of "thought").

Syntactic Bootstrapping for Verbs

• Children pay attention to syntactic structures to infer meanings of new verbs.

Summary and Conclusions

• Language acquisition involves numerous challenges, including segmenting continuous speech and associating words with meanings.

• Infants are naturally equipped to learn language efficiently through various cognitive strategies.

• The roles of statistical learning, prosody, and social cues all contribute fundamentally to the process of language development in early childhood.