Childhood Sp/snd dis: Theories

Behavioral Theory of Speech & Language

speech and language as learned verbal behavior

Emphasis on observable behaviors and environmental contingencies

Central to traditional articulation therapy

Foundational theorist: B. F. Skinner

Operant Conditioning Framework

Speech as operant behavior

Behavior shaped by consequences: Positive reinforcement → increased frequency, Negative reinforcement → decreased frequency

Learning explained via stimulus–response–consequence sequences

Babbling as Operant Behavior

Babbling viewed as behavior subject to reinforcement

Caregiver responses shape early vocal output

Reinforcement assigns communicative value to infant vocalizations

Phonological development emerges through repeated contingencies

Generative Phonology

Extension of distinctive feature theory

Focuses on how sounds are: Represented mentally, Transformed into spoken output

Key figures: Chomsky & Halle; Elbert & Gierut

Underlying (Phonological / Deep Structure)

Abstract mental representation

Stored in the lexicon

Surface (Phonetic Structure)

Physical realization

Produced by the vocal tract

Naturalness and Markedness

Continuum of production complexity

Naturalness

Easy to produce

Frequent cross-linguistically

Acquired early (e.g., /t/)

Markedness

Complex

Less frequent

Acquired later (e.g., /ʤ/)

Linguistic Notation: _________________# indicates

A sound in the word final position

Linguistic Notation: #_________________ indicates

A sound in the word initial position.

Generative phonology explains:

Mental representation of sounds

Rule-governed surface realizations

Integrates linguistic theory with clinical analysis

Emphasizes systematic, feature-based patterns

Natural Phonology

Stampe (1969, 1979) used the idea of rules from generative phonology plus concepts of naturalness, markedness, and features to explain why young children tend to pronounce words in similar less mature ways. Children’s pattern-based rules were referred to as phonological processes

Phonological processes

a simple way of describing the systematic error patterns in children’s speech

There are three broad categories of phonological processes: syllable structure processes, substitution processes, assimilatory processes

Syllable Structure Processes

Weak (unstressed) syllable deletion, Reduplication, Final consonant deletion, cluster reduction, epenthesis

Weak (unstressed) syllable deletion

Deletion of unstressed syllable

/bənænə/ -> [nænə]

Reduplication

Repetition of syllable

/bɑtəl/ -> [bɑbɑ]

Final consonant deletion

Deletion of final consonant

/bot/ -> [bo]

Cluster reduction

Delete part of cluster

/stɑp/ -> [tɑp]

Epenthesis

Add schwa

/blu/ -> [bəlu]

Syllable Structure Processes

Coalescence, Diminutization, Migration, Metathesis, Initial Consonant Deletion

Coalescence

Two sounds combine to one

/spun/ -> [fun]

Diminutization

Add /i/

/dɔɡ/ -> [dɔɡi]

Initial Consonant Deletion

Deletion of initial consonant

/haʊs/ -> [aʊs]

Metathesis

First sound switch spots

/spəɡɛti/ -> [psəɡɛti]

Migration

Beginning sound goes to end

/ski/-> [kis]

Substitution Processes

Stopping, gliding, fronting, vocalization, vowelization, affrication, deaffrication, consonant cluster substitution, derhotacization, denasalization, context sensitive voicing.

Stopping

Stopping is the substitution of a stop (b, p, t, d, k, g) sound for a fricative (f, v, s, z, h, th, sh, zh) or affricate (ch, j) sound

/si/-> [ti]

Gliding

a form of substitution, where a child will produce a W or occasionally a Y for R and L sounds.

/reɪ/ -> [weɪ]

Fronting

substitution of a sound produced in the back of the mouth with a sound produced in the front of the mouth

/ki/ -> [ti]

Vocalization/ Vowelization

substitutive process involves articulating vowel sounds instead of the liquid class of sounds, including “R” and “L.”

/teɪbəl/ -> [teɪbo]

Affrication

the substitution of an affricate (ch, j) sound for an nonaffricate sound

/ʃɑp/ -> [ʧɑp]

Deaffrication

the substitution of an non-affricate sound for an affricate sound

/ʧip/-> [ʃip]

Consonant cluster substitution

This process occurs when one consonant sound in a cluster is substituted for another sound.

/strit/ -> [stwit]

Derhotacization

When a sound loses it’s r-coloring

/fɝ /-> [fɜ]

Denasalization

When a sound loses it’s nasality

/nun/ -> [dud]

Context sensitive voicing

This is the process when an unvoiced sound becomes voiced sound.

/tɛn/ -> [dɛn]

Prevocalic voicing

Sound before the vowel becomes voiced

/tɔɪ/ - [dɔɪ]

Postvocalic devoicing

Sound after vowel is NOT voiced

/ʃuz/ → [ʃus]

Assimilation can be:

progressive OR regressive

AND

labial, velar, alveolar, palatal, nasal or liquid

Psycholinguistic Model

Psycholinguistics: study of human linguistic behavior

Focus on internal cognitive mechanisms underlying speech

Key goal: explain how speech is perceived, stored, planned, and produced

Psycholinguistic models describe

components of speech processing

Move beyond surface errors to identify processing-level breakdowns

Particularly useful for explaining variability in speech sound disorders

Stackhouse & Wells Speech Processing Model

Four core components: • Perception • Storage • Planning • Production

Often represented as a box-and-arrow mode

The Speech Processing Model purpose is to

illustrate the relationship between:

• Receptive processing of speech

• Phonological storage

• Planning and execution of phoneme sequences

• Explains why perception and production may dissociate

Lexical representation: Single-lexicon models and Two-lexicon models differ in

how perception and production are represented

Single-Lexicon Models

• Assumed: Adult-like representations stored

• Accurate perception

• Limitation: Cannot explain persistent production errors

Two-Lexicon Models

Distinguish between:

• Input lexicon: perceived adult-like form

• Output lexicon: child’s production form

• Explains perception–production mismatches

Full Speech Processing Sequence

Peripheral auditory processing

• Phonological recognition

• Development of phonological representation

• Motor programming and planning

• Motor execution

• Breakdown can occur at any stage