Speech and Language Development Notes

Learning Objectives

  • Describe four theories of speech and language development.
  • Explain the stages of speech development.
  • Explain the stages of language development.

Speech Development

  • Involves the progressive evolution of individual sounds and syllables.
  • Uses arbitrary symbols to create words for communication, conveying wants, needs, thoughts, feelings, and knowledge.

Language Development

  • Involves the growth of a communication system to represent concepts via arbitrary symbols (sounds/words) and grammar.

Theories of Speech & Language Development

  1. Behavioral Theory

    • Founder: B. F. Skinner, father of modern behavioral theory.
    • Core Idea: Language is learned through operant conditioning (reinforcement of verbal behaviors).
    • Process: Child imitates heard words, receives reinforcement for close approximations, leading to further shaping of language skills.

  2. Nativist Theory

    • Focus on language as an innate and biologically predetermined process.
    • Suggests children are “prewired” for language acquisition, which occurs naturally rather than being explicitly taught.
    • Clinical Insight: Issues in natural learning may indicate areas requiring therapeutic intervention.

  3. Semantic-Cognitive Theory

    • Emphasizes the link between cognitive understanding and language development.
    • Children often know what they want to communicate but may struggle with the correct use of semantics or grammar.

  4. Social-Pragmatic Theory

    • Views communication as the essential function of language.
    • Importance of turn-taking in both verbal and non-verbal interactions.
    • Clinical Insight: Caregivers play a crucial role in language development by responding to a child's sounds and gestures.

Phonological Development

  • Language universals affect the age and order in which sounds are acquired.
  • Simpler sounds, favorable for articulation, are usually acquired early, while more complex sounds are developed later.

Consonant Acquisition in English

  • Consonants Overview

    TypeVoicelessVoiced
    Bilabialp (pea), m (men)b (bee)
    Labiodentalf (fig), v (vest)
    Dentalθ (thumb)ð (them)
    Alveolart (tea), s (sea)d (dig)
    Velark (king)g (gap)
    Glottalh (high)

  • Early-, Middle-, and Late-Developing Sounds

    • Early 8: /m, b, j, n, w, d, p, h/
    • Middle 8: /t, ŋ, k, g, f, v, ð, ʒ/
    • Late 8: /ʃ, θ, s, z, l, r, dʒ, ŋ/

Mean Length of Utterance (MLU)

  • defined as:
    MLU = rac{Total ext{ number of morphemes}}{Total ext{ number of utterances}}

Example of MLU Calculation

  • Utterances:
    1. I see daddy. (4)
    2. More juice. (2)
    3. What man doing? (4)
    4. Mommy driving. (4)
    5. Ball in cup. (3)
    6. Baby pulled the wagon. (6)
    7. The girl likes eating. (5)
    8. He's falling down. (4)
    9. The bus is yellow. (5)
    10. Where mommy go? (3)
  • MLU Calculation:
    MLU = rac{38}{10} = 3.8

Brown's Stages of Grammatical Morpheme Development

  • Stages
    • I: 1.5-2.0 MLU: Combine basic words. (12-26 months)
    • II: 2.0-2.5 MLU: Modulation of meaning via grammatical morphemes. (27-30 months)
    • III: 2.5-3.0 MLU: Complex sentence emergence. (31-34 months)
    • IV: 3.0-3.75 MLU: Conjoining sentences, noun phrase elaboration. (35-40 months)
    • V: 3.75-4.50 MLU: Further complex and compound sentence development. (41-46 months)

Key Terms & Concepts

  • Speech development
  • Language development
  • Behavioral Theory
  • Nativist Theory
  • Semantic-Cognitive Theory
  • Social-Pragmatic Theory
  • Early 8/Mid-8/Late 8 sounds
  • Mean Length of Utterance (MLU)
  • Brown’s Morphemes