Language Acquisition: Overview

Introduction to Language Acquisition

• Language acquisition is the process by which humans learn to communicate through language.

• Factors influencing language acquisition include the language environment, age of exposure, and individual differences.

Age and Language Exposure

• From birth to 5 years, the number of languages regularly spoken at home impacts language development.

  • A. One Language

  • B. Two Languages

  • C. More than Two Languages

Household Language Use

• The language spoken during childhood shapes language acquisition.

  • A. English Dominant Households

  • B. Spanish Dominant Households

  • C. Bilingual Households (English and Spanish)

  • D. Non-English/Spanish Households

Linguistic Diversity

Global Language Statistics

• Approximately 23 languages spoken by over 4 billion people, making up about half the world's population.

• Over 7,000 languages are currently alive around the globe.

• Universal in development: Typically developing humans learn at least one language.

Complexity of Language Acquisition

• Learning involves understanding:

  • Sounds

  • Rhythms

  • Words

  • Grammar

  • Gestures

  • Signs

  • Multiple languages

Speech Perception

Understanding Phonemes

• Phoneme: The smallest unit of speech that can distinguish one word from another.

  • Example: /b/ vs. /k/ differentiates "bat" from "cat."

Research Insights

• Dr. Janet Werker's research on speech perception in infants.

• Head Turn Procedure (Werker 1989):

  • Phase 1: Teach infants to turn their heads in response to sound changes.

  • Phase 2: Measure head turns in response to phonetic changes.

Developmental Phonetic Discrimination

• At 6-8 months, English-learning infants can discriminate non-English phonemes.

• By 10-12 months, they begin to lose this ability—demonstrating perceptual narrowing.

Perceptual Narrowing

Effects of Age on Phoneme Discrimination

• As infants grow, their ability to discriminate between phonemes decreases unless they are exposed to a variety of languages.

• This phenomenon is known as perceptual narrowing.

Group Discussion Prompt

• Recommendation for parents wishing their baby to learn a language: Consider the best approach to language exposure (e.g., live interactions vs. recordings).

The Role of Source in Language Learning

Kuhl et al. Research (2003)

• Study comparing Mandarin speech perception in American infants vs. native Mandarin learners.

• Findings showed:

  • Live Interaction: Critical for babies' language learning processes.

  • Audio/Visual Exposure: Less effective than live interactions.

Experimental Groups in Kuhl Study

• Groups: Live interactions, TV, Audio sessions.

• All groups underwent 12 experimental sessions with Mandarin exposure.

Infant-Directed Speech

Characteristics of Infant-Directed Speech

• Speech adjusted for infants includes:

  • Higher intonation

  • Slower tempo

  • Shorter words

  • Repetition

  • Increased questioning

• Common across multiple languages including Arabic, French, Japanese, Mandarin, Turkish, and English.

Preferences in Infant-Directed Speech

• Studies consistently show that infants prefer infant-directed speech compared to adult-directed speech.

• Infants' interest in infant-directed speech increases with age.

Research Methods Used

• Various methodologies in studies include:

  • Eye-tracking

  • Head-turn preference procedures

  • Central fixation techniques