Normal Phonological Development: Speech Sound Disorders

NORMAL PHONOLOGICAL DEVELOPMENT

Speech Sound Disorders

Chapter 5 - Fall 2025

Structural and Functional Development

  • Changes in all processes of speech:
    • Respiratory Development:
    • Lungs are larger compared to the infant’s size, with only 1/3 to ½ of all alveoli present at birth.
    • High levels of subglottal pressure present.
    • The respiratory system continues to grow until 7 or 8 years of age.
    • Phonatory Development:
    • Laryngeal cartilages are larger, limiting room for vocal fold vibration.
    • The larynx is situated higher in the pharyngeal space at birth and grows to a proportionate adult size, descending to the appropriate area.
    • Vocal folds lengthen as the child grows; the epiglottis becomes firmer.
    • Resonatory Development:
    • The descent of the larynx creates more room in the pharynx for resonance.
    • Articulation Development:
    • At birth, the tongue is large and sucking pads occupy most of the oral cavity.
    • As the infant grows, oral structures develop, and the tongue becomes proportionate to the mandible, lip, and velar movements, allowing for speech production.

Auditory Skills

  • Fetal Hearing Development:
    • By gestational week 25, babies begin to hear voices; they can recognize voices as early as week 27.
    • Sounds may be muffled due to vernix covering the ears.
    • Fetal movements may change in response to sounds (e.g., a fetal jerk after a loud noise).
    • A baby’s heart rate can slow down when hearing the mother’s voice, indicating recognition and comfort.

Auditory Discrimination

  • Infants show a preference for human speech over other sounds.
  • Developmental Milestones:
    • Infants turn towards noise within the first week of life.
    • By three days of age, an infant recognizes its mother's voice.
  • Research Methods:
    • High-amplitude sucking method.
    • Visually-reinforced head turn method.

Speech Production

  • Initial Vocalizations:
    • Infants start with reflexive vocalizations such as crying, coughing, and sneezing.
    • Gradually increase speech sounds until the first word is typically produced around the first birthday.

Oller’s Stages of Vocalization

  • Stage 1: Phonation (Birth – 2 months):
    • Primarily reflexive vocalizations.
  • Stage 2: Coo and Goo (1-4 months):
    • Production of back consonants and back vowels.
    • Emergence of VC and CV syllable shapes.
  • Stage 3: Expansion (3-8 months):
    • Involves vocal play including squeals, yells, and raspberries.
    • Development of babbling featuring CV and VC strings of syllables.
  • Stage 4: Canonical Babbling Stage (5-10 months):
    • Also known as reduplicated babbling involving regular production of CV strings of reduplicated syllables (e.g., ma-ma, da-da, buh-buh).
    • Variants include variegated babbling with strings of varied CV productions.
  • Stage 5: Integrative Stage (10-18 months):
    • Production of jargon—meaningful words mixed with non-meaningful gibberish, showcasing adult-like intonation including statements and questions.

Transition from Babbling to Meaningful Speech

  • Characteristics:
    • True words are attempts at adult production, used consistently by the child.
    • Protowords (Vocables, Phonetically-Consistent Forms - PCFs):
    • Consist of vocoids and contoids.
    • Progressive Idioms:
    • Advanced forms that are used at the word level but may not be applied contextually.
    • Regressive Idioms:
    • Static pronunciations, showcasing that certain pronunciations never change over time (e.g., reduplication exemplified by /kiki/).

The First 50-word Stage

  • Age Range: 12-24 months.
  • Characteristics of Vocabulary:
    • Primarily monosyllabic words.
    • Frequent use of stop consonants over nasals and fricatives.
    • Rare occurrence of consonant clusters.
    • Common vowels are central, mid-front, and low-front.
    • Predominant syllable structures include CV, VC, CVC.
  • Understanding vs. Expression:
    • Children express around 50 words but can understand up to 200.

Prosody

  • Definition:
    • The way in which something is said, referring not only to the pitch and loudness influencing meaning but also to emotional intent.
  • Research Findings:
    • Larger consonant inventory present in the initial position.
    • Voiced stops appear more frequently than voiceless in initial position.
    • In word-final position, voiceless stops were heard more often than voiced stops, with 50% of subjects at 24 months demonstrating this.

Development of Stress and Pitch

  • 14-24 months:
    • Development includes falling contour and lengthening of vowels.
  • 13-15 months:
    • Speech acts develop, including requesting, curiosity, and surprise, characterized by a rising contour followed by a falling contour in speech.
  • Prior to 18 months:
    • Anticipation and emphatic stress become evident, including various pitch contours.
  • Around 18 months:
    • Development of warnings and playful speech, falling-rising and rising-falling contours appear.

Contrastive Stress

  • Age of Development:
    • Emerges around the time children start using two-word combinations at the age of two years.
  • Characteristics:
    • Initially, one syllable will contain more stress than the other in two-word combinations.
    • Gradual shortening of the pause between words facilitates blending into a tone-unit. Stress placement indicates meaning.

Acquisition of Speech Sounds

  • Normative Studies:
    • Variations in definitions of "mastery" including aspects like word positions considered, population size, and study location (longitudinal vs. cross-sectional studies).

Sound Class Development

  • Early-Developing Classes:
    • Nasals, Stops, Glides.
  • Late-Developing Classes:
    • Fricatives, Affricates, Liquids.

Common Phonological Processes

  • Syllable Structure Processes:
    • Final consonant deletion.
    • Cluster reduction.
    • Weak syllable deletion.
  • Substitution Processes:
    • Stopping.
    • Fronting.
    • Gliding.

Processes That Disappear by Age 3 vs. Processes That Persist Beyond Age 3

  • Disappearance (by 3 years):
    • Weak syllable deletion.
    • Final consonant deletion.
    • Diminutization.
    • Fronting.
    • Reduplication.
  • Persistence (beyond 3 years):
    • Prevocalic voicing.
    • Assimilation.
    • Cluster reduction.
    • Epenthesis.
    • Gliding.
    • Vocalization.
    • Stopping.
    • Depalatalization.
    • Final consonant devoicing.

Analyzing the Sound System

  • Examination includes:
    • Consonants and Vowels?
    • Syllable shapes?
    • Placement of articulators?
    • Manner of airflow?
    • Voiced vs. voiceless sounds?
    • Distinctive features?
    • Phonological processes?

Speech Intelligibility by Age

  • Intelligibility Percentages:
    • 19-24 months: 25 – 50% intelligible.
    • 2-3 years: 50 – 75% intelligible.
    • 4-5 years: 75 – 90% intelligible.
    • 5+ years: 90 – 100% intelligible.

School-age Sound Development

  • At Age 5 (Kindergarten):
    • Children engage in free conversation; speech becomes intelligible.
    • Adapt conversation style to peers.
    • Segmental form of speech sound production fine-tunes as they grow.
    • Mastery of sounds often not achieved until around 9 years old.
    • Development of consonant clusters may happen as early as 2 years, but accuracy improves over time.
  • Phonological Patterns:
    • Common patterns include cluster reduction, sound lengthening, and epenthesis (insertion of schwa).

Morphophonology

  • Definition:
    • The study of how an allophone that is rooted in a phoneme becomes an allomorph to manipulate meanings of words.
  • Progression:
    • Children must have developed their phonological systems to use allophones as needed in morphemes effectively.

Development of Phonological Awareness

  • Definition:
    • Awareness that words are composed of sounds.
  • Key Skills:
    • Rhyming.
    • Alliteration (identifying words that begin or end with certain sounds).
    • Phoneme Isolation:
    • Identifying where a specific sound occurs within a word.
    • Sound Blending:
    • Blending 2 or more sounds presented in a temporally-spaced manner.
    • Syllable Identification:
    • Identifying the number of syllables in a word.
    • Sound Segmentation:
    • Breaking a word into its component sounds (inverse of sound blending).
    • Invented Spelling:
    • Spelling words phonetically.

Distinctions in Phonological Concepts

  • Metaphonology:
    • Awareness of language sounds and their combinations.
  • Phonological Processing:
    • Use of language sounds to process both oral and written information.
  • Phonological Awareness:
    • Considering sound structure separately from sound meaning to manipulate sounds or syllables for word generation.
  • Phonemic Awareness:
    • Understanding words as combinations of individual phonemes that can be manipulated to form new words.

Phonological Memory and Retrieval

  • Phonological Memory:
    • Ability to code phonological information temporarily for immediate recall; important for vocabulary acquisition.
  • Retrieval from Long-term Memory:
    • Necessary for associating sounds with meanings and formulating words when speaking or reading.
  • Importance of Awareness Skills:
    • Syllable awareness, onset-rime awareness, and phonemic awareness are crucial for written language; strong phonological skills correlate with reading strengths.

References

  • Bauman-Wängler, J. A. (2020). Articulation and phonology in speech sound disorders: A clinical focus.
  • Peña-Brooks, A., & Hegde, M. N. (2007). Assessment and treatment of articulation and phonological disorders in children: A dual-level text.
  • Reading Rockets (2016). Turning in to Speech Sounds. Retrieved September 23, 2025, from https://www.youtube.com/watch?v=WvM5bqUsbu8.
  • UW I-Labs (2013). Babies Learn Language in the Womb. Retrieved September 23, 2025, from https://www.youtube.com/watch?v=psgv41HVdaE