Language Development

Language Development

Overview of Lecture

  • Course: PSYC 3500, Winter 2026

  • Instructor: Dr. Carolyn Baer

  • Lecture Focus: Understanding how we learn to communicate

Lecture Outline

  • Speech Perception

  • Word Comprehension

  • Speech Production

  • Tie-in to Theories

  • Deep Dive: Bilingualism

Speech Perception

Starting Point

  • Review of last week's content: Newborn preference for familiar sounds, supported by the Cat in the Hat study.

  • Newborns distinguish familiar prosody including rhythm and pitch patterns of speech.

  • Inquiry: Is all speech perception based on prior experience?

Phonology (Spoken Language)

  • Definition: Languages consist of phonemes, which are meaningful units of sound.

  • Examples:

    • /r/ in rake vs. /l/ in lake.

    • English has approximately 45 phonemes; globally, there are about 200 phonemes.

  • Phonemes exist on a continuum but are perceived categorically by speakers.

Voice Onset Time (VOT)

  • Definition: VOT is the duration between the start of vocal cord vibration and the airflow passing through the lips.

  • Reference to relevant online video for demonstration.

Phonetic Discrimination

  • Infants show a learned response by visually tracking a dancing bunny when phonemes change.

  • Infants are considered universal listeners at birth, able to detect all phonemes. However, by 10 months, they lose sensitivity to phonemes not present in their native language.

  • Reference: Study by Werker & Tees, 1984.

Intermodal Perception

  • The McGurk effect is introduced, illustrating that phoneme perception is affected by visual information.

  • Evidence shows this ability presents in infants as early as 4-5 months.

  • Reference to an online video demonstration of the McGurk effect.

Phonemes in Context

  • Reading fluent speech without clear word boundaries can make word segmentation difficult.

  • Word Segmentation: The process of identifying where one word ends, and another begins in continuous speech.

Word Segmentation Studies

  • Inquiry into whether infants utilize statistical properties of speech for parsing.

  • Experiment: 8-month-old infants listen to a speech stream for 2 minutes: "bidakupadotigolabubidakugolabupadotipadolatibidaku".

  • Comparison metrics:

    • Bi -> da: 100% success rate.

    • Ti -> go: 33% success rate.

  • Reference: Study by Saffran, Aslin & Newport, 1996.

Experiment Results

  • Data showing infants look longer at "bidaku" (100% frequency word) versus "tigola" (33% frequency) indicates learned segmentation.

  • Recent findings indicate newborns can perform similar segmentation tasks.

Additional Cues for Segmentation

  • Stressed syllables: Infants learning English show that stress is predominantly on the first syllable of words.

  • Infant-Directed Speech (Parentese"): Characterized by higher pitch and exaggerated syllable boundaries, which helps segment words.

Research on Infant-Directed Speech

  • Many Babies Consortium, 2020: Study involving 69 labs and 2329 babies shows:

    • Preference for infant-directed speech, particularly in North American English environments.

    • Notable increase in preference with age.

Recap on Speech Perception

  • Infants begin with a preference for sounds reminiscent of familiar speech, retaining phonetic sensitivity until approximately 10 months.

  • Statistical regularities and stress patterns in speech assist infants in word recognition, facilitated further by preference for infant-directed speech.

Learning Words

Sound to Meaning

  • Definition: Phonemes combine to form morphemes, which are the smallest units of meaning in speech.

    • Examples:

    • Free morphemes: dog, cat, flower.

    • Bound morphemes: -s, de-, -ing.

  • Language is generative, allowing finite elements (phonemes/morphemes) to create an infinite number of sentences.

  • Average English speaker knows approximately 60,000 morphemes.

Earliest Word Comprehension

  • Notable milestones:

    • Recognizing their own name by 4.5 months of age.

    • Understanding frequently used words by 6 months, evidenced through eye-tracking showing longer gaze at matching referents (e.g., baby looks at a mouth upon hearing the word "mouth").

    • This comprehension is consistent for infants, including those on the autism spectrum.

Mechanisms of Word Learning

  1. Fast Mapping: Rapidly learning word-object associations.

    • Example: Using the term "chromium tray" versus "red one"; remembered the label a week later.

    • Reference: Study by Carey & Bartlett, 1978.

  2. Whole Object Assumption: The basic assumption in language learning that words refer to whole objects, not their parts or features.

    • E.g., hearing the word "fish" typically refers to the entire fish rather than just its scales.

  3. Mutual Exclusivity: The principle that each object has only one name, guiding children in assigning names to unfamiliar objects while recognizing known ones.

  4. Shape Bias: Children generalize labels based on shape;

    • Example: Understanding“dog” to refer to 4-legged animals but may overextend to non-related entities based on shape (e.g., all four-legged creatures).

    • Shape bias increases with age based on related studies (e.g., Landau, Smith & Jones, 1988).

Cultural and Language Variations

  • Not all languages emphasize object naming:

    • English distinguishes count nouns (objects that can be quantified, such as cup) from mass nouns (substantial materials, such as milk).

    • Other languages, i.e., Yucatec Mayan, focus more on materials, while Japanese employs versatile grammar for nouns.

  1. Grammatical Cues: Examples demonstrating how syntax impacts understanding words;

    • Utilizing the term "sibbing" can be interpreted variably based on syntax (context): as an action, as a container, or as a material.

    • Reference: Study by Brown, 1957.

  2. Pragmatic Cues: Language understanding involves social context, i.e., how language is used socially:

    • Define Pragmatics: The study of language use in social situations, enhancing intersubjectivity (mutual understanding during communication).

    • Joint Attention: Social partners focusing on the same external element, theorized as crucial for human communication (cited Tomasello and associated sociocultural theories).

Contextual Learning Cues

  • Contextual studies involving 13-month-olds observed interactions with mothers in various settings (mealtimes, grooming, book reading) to analyze the vocabulary students encountered in respective contexts, revealing significant correlations in word types (Tamis-LeMonda et al., 2019).

Vocabulary Development Recap

  • Vocabulary comprehension begins as early as 4.5-6 months.

  • Learning mechanisms include fast mapping, whole object assumption, mutual exclusivity, and shape bias, enabling children to grasp meanings.

Speech Production

Babbling Phase

  • Begins roughly between 6-10 months, including for children using sign language, to foster conversational turn-taking and indicate readiness for further learning.

First Word Milestones

  • First words typically occur between 10-15 months (average around 12 months).

  • Criteria for first words:

    • Vocalization expressing meaning with consistent context (e.g., "ba" around a ball).

  • Common first words about people and significant objects, actions, and social routines (e.g., mama, up, gone).

Measuring Vocabulary Development

  • Vocabulary assessed using standardized tools such as the MacArthur-Bates Communicative Development Inventory (CDI).

  • Notable tools and data resources to explore include interactive vocabulary growth datasets.

Individual Differences in Language Input

  • Study highlighted in Hart & Risley, 1995 suggests large disparities in words heard by children pre-school and their vocabulary at age three.

  • Notable statistics:

    • Some communities exposed to significantly less child-directed language compared to others.

  • Examples highlighting diverse cultural practices:

    • Tsimane children in Bolivia showing under 1-minute child-directed input daily.

  • Learning through observation rather than direct communication also examined (Akhtar, 2005; Rogoff et al., 2003).

Formation of Sentences

  • Two-word sentences emerge by approximately 24 months, characterized by distinctive patterns like:

    • Agent-object (e.g., "Daddy book")

    • Action-object (e.g., "eat dessert")

  • Disallowed word orders include variations that differ from established two-word sentence grammars, indicating an innate structure in language processing.

Grammatical Learning

  • Overgeneralization of grammatical structures, such as regularizing verbs;

    • Examples include using walked for walk and went for go.

  • Emphasis that correction does not significantly influence language learning due to inherent complexities in language acquisition.

Conversational Skills

  • Children’s conversations often revolve around random topics, which reflect their expanding cognitive processing:

    • Knowledgeable approach compared with ignorant retelling, pegged to storyline quality and listener engagement.

    • Reference: Baer & Friedman, 2018.

Summary of Speech Production

  • Babbling builds foundational skills leading to first words around 12 months.

  • Vocabulary changes substantially around 18 months; individual variances due to amount of speech exposure noted.

  • At two years, toddlers often produce two-word sentences, exhibiting conversational skills about topic selection and turn-taking.

Deep Dive into Bilingualism

FAQs on Child Bilingualism

  1. Is bilingualism beneficial?

  2. Does it impact first language learning?

  3. When is the optimal time to start learning another language?

Bilingualism Benefits

  • Bilingual children manage two sets of vocabulary and grammar, enhancing cognitive flexibility and perspective-taking:

    • Cognitive agility is associated with practice in switching between tasks and adapting to different communicative scenarios.

Cognitive Measures of Flexibility

  • Dimensional Change Card Sort Task: This task measures cognitive flexibility.

    • Findings illustrate that bilingual children exhibit better cognitive flexibility compared to their monolingual peers.

  • Reference: Bialystok & Martin, 2004 suggest that bilingual 4-5 year-old individuals scored higher in flexibility tasks.

Perspective-Taking Studies

  • Three-year-olds demonstrated improved responsiveness in understanding another's needs, evaluated using puppet play tasks.

    • Result: Bilingual children showed higher responsiveness.

    • Study: Gampe, Wermelinger & Daum, 2019.

Bilingualism and First Language Learning

  • Clarification on language confusion: Although bilinguals may have smaller vocabularies in each of their languages, they possess a balanced vocabulary across both languages overall.

Optimal Timing for Language Learning

Critical Periods for Phoneme Recognition

  • Initial universal ability to hear phonemes narrows around 9 months; followed up by studies exposing infants to Hindi phoneme environments.

  • Highlights that early exposure to diverse phonemes in second languages enhances retention

  • Reference studies by Yoshida et al., 2012 and Kuhl et al., 2003 show live versus recorded speaker effects on phoneme retention.

Critical Period for First Language Acquisition

  • Proficiency related to early exposure nurtured language fluency (Newport, 1990) specifically for sign learners.

  • Comparatively, studies show Korean immigrants’ success in learning English relates to the age of acquisition (Johnson & Newport, 1990).

Bilingualism Recap

  • Benefits of bilingualism include cognitive flexibility and enriched perspectives.

  • Vocabulary development appears normal but begins smaller in individual languages.

  • Early phonemic discrimination is more effective when started prior to ages 5-7 but does not exclude the potential for later learners.

Final Notes

  • Upcoming tasks:

    • Attend seminar sections W01 and W03 for observational studies.

    • Complete TCPS2 ethics training if not completed.

    • Finish Quiz 3.

    • Submit Reflection 3.