Models of phonological development

Models

• Traditional• Linguistic• Psycholinguistic

Behaviorist Model - Traditional

• Role of contingent reinforcement (environment) in speech acquisition

• Child’s babbling shaped through operant principles – Skinner

• Child associate vocalizations of caretaker with• Primary reinforcement such as food and comfort• Secondary reinforcement is adult’s vocalization

• Caretaker continues to reinforce• There is self-reinforcement

Generative Phonology Model – Linguistic Models

• Innateness and universality – Chomsky• Phonological rules map representations from deep to surface

structures*• Phonological rules are dependent on information from other

linguistic levels.• Distinctive features

• Child looks at the adult model and rewrites it into his model

• Different way of organizing from adult • Universal tendencies innate or learned very early• Child can process and it is in their production that there are

problems

Natural Phonology Model – Linguistic Model – Stampe

• Natural processes (patterns) are preferred or used.• Those Universal across languages• Those frequently used by young children

• Emphasized universal and maturational aspect of phonological acquisition

• Child comes innately with a natural set of phonological processes that reflect the natural limitations and capacities of human vocal production and perception. (operations to delete or change phonological units)

Natural Phonology Model – Linguistic Model – Stampe

• Child’s task is to suppress those processes which do not occur in the particular adult language to which he is exposed.

• Child can process (can represent at the deep level the adult sound), it is in the production that there are problems

Non-linear Phonology Model – Linguistic Model - Goldsmith

• Refers to a collection of theories that focus on the hierarchical nature of the relationships between phonological units

• Production of speech involves more than just the production of phonemes, other elements influence

• Two main tiers – prosodic (word, foot, syllable, onset-rime, skeletal-word shape) and segmental (speech sounds and features)

Optimality Theory – Linguistic Model – Prince and Smolensky

• Basic units are constraints• Markedness constraints – limits what is

permissible in a language, sounds that are difficult to produce or perceive are marked

• Faithulness constraints – features to be preserved.

Sonority Hypothesis – Linguistic Model –

• Refers to the relative loudness of a sound relative to other sounds with same pitch, stress, and length.

• Voicing is important• Sounds are given a numerical value to represent

degree of sonority.• Sounds with low sonority value are found at the

syllable margina and sounds wit high sonority values are located toward the center.

Psycholinguistic Models

• Explains children’s phonology by looking at perception, storage, planning and production in real time

• Describes underlying representations of words and their production

• They are interested in what happens between input and output. In between is a “black box” containing underlying representations or phonological information stored in the brain about words known and used (lexicon).

• Two lexicon model: one that holds words that are adult like perceptual representations, and a second lexicon which contains words that have already been transformed.

Others not in the book

Structuralists - Jakobson

• Phonological development follows a universal and innate order of acquisition

• Distinctive features are arranged in a hierarchy• Distinctive features unfold in a predictable order

as the child produces phonemic contrasts embodying them.

• Child continues to learn new feature contrasts• Babbling has nothing to do with the development

of the sound system

Prosodic Model - Waterson

• Focus on the word as the basic unit• Early words are schemas/templates that

share features of adult forms (intonation pattern, syllable structure, presence of fricatives or voicing.

• Child’s perception and production of adult features is imperfect and must undergo development and change

Cognitive Model

• Problem solving model• Child encounters challenges• Individual strategies dependent on natural

predispositions and external factors• Different children begin mastering different

articulatory patterns by attempting to produce different adult words

Biological model - Locke

• Innate perceptual biases and dispositions to certain motor action

• Babbling is phonetic repertoire is universal, constrained by physical structure and size of mouth, articulators, etc.

• Language environment starts to influence as of first words• Depends on storage and retrieval of some relatively stable

perceived forms of language• Developmental mechanisms

• Maintenance (of babbling patterns found in adult language• Learning (of non babbling patterns not found in adult language• Loss (patterns not found in adult)

Self-Organizing Model - Lindblom

• Converges biological and linguistic models• Phonetic forms in all languages have

evolved to meet the complementary needs of the two participants in vocal communication• Listener• Speaker

Self-Organizing Model -Performance constraints

• Needs of the listener are met – Ex. when a language uses vowels that are maximally distant from one another and easy to discriminate

• Needs of speaker are met – needs of speaker are met when language uses consonant-vowel sequences which require little tongue movement and are easy to articulate

• Compromise between these two sets of performance constraints leads to • phonetic universals or core segments – used in all languages• and • exotic segments which occur only in languages with large

phonetic inventories

Self-Organizing Model – Performance Constraints

• A small set of articulatory gestures are used over and over in different combinations to produce word patterns or syllables

• Children use a small number of articulatory gestures which relate to core segments over and over again in different word patterns.

• This use will lead to the emergence of a network of phonologically contrastive segments (individual sounds emerging from the above syllables) – self-segmentation

Development

Infant Perception

Problems faced by infants

• Segmentation Problem

• Perceptual Constancy Problem

Segmentation Problem

• English vowel lengthening is related to• Syllable stress• Voicing differences• Word boundaries• Clause boundaries

• What are the correct cues for segmenting words????

• Children must learn the segmentation problems with information processing and memory resources less than that of adults.

Abilities Needed to Master Language

• Deal with speech variability• Vocal tract differences• Acoustic characteristic of word differ by

speaker = perceptual constancy problem• Differences within a particular speaker• Changes in production because of phonetic

contexts

Children must learn which phones serve as elementary

sound units for forming words in their language.

Learning words and building a lexicon

• Ability to segment fluent speech necessary• Aspect of learning involves storing some

information about the sound pattern of the word that allows its meaning to be accessed. It must sufficient to distinguish one word from another allowing variability.

Some Suggested Strategies

• Grouping of utterances into clauses and phrases.

• Acoustic markings in speech directed to infants

• Unstress and omit function words

Prosody and Bonding

Categorical Perception

• Acoustic cues relevant to speech sounds• Voicing• Aspiration• Place of articulation

Solving the Segmentation Problem

• Phonetic predisposition• Attunement to abrupt discontinuities

Vocal and Articulatory Control

Needed Before Learning Speech (Oller, 1976)

• During first year phonological development helps children attain the following competencies.

Vocal and Articulatory Control

Needed Before Learning Speech (Oller, 1976)

• Control of phonation or voice and the vocal mechanism.• turn voicing on and off at will.

• Control of extremes and variations in pitch.• first learn to make the distinctions between very high

sounds and very low sounds.

• then learn to make finer pitch variations, which are necessary for intonation patterns.

Vocal and Articulatory Control

Needed Before Learning Speech (Oller, 1976)

• Control of extremes and variations in volume• Gain voluntary control over extremes in

volume• Helps between yelling and speaking softly• Helps distinguish fine variations for word and

sentence stress• Helps adjust volume to different listeners and

speaking situations

Vocal and Articulatory Control

Needed Before Learning Speech (Oller, 1976)

• Control of resonance• Full use of resonant qualities not in their earliest

utterances• Then they learn resonance for appropriate voice

quality required for different speech needs• Control of timing aspects of alternating resonance

and constrictions• Open and closed positions of the vocal tract develop

into consonants and vowels• They must become very rapid

Stages of Production

• Typologies – go to page 87

Children’ vocalizations

• 1.5 month old• 3 month old• 7 month old• 11 month old• 13 month old• 17 months

Sequence of Speech sound Acquisition – Bleile

• Phase 1: Laying the foundations for speech (birth to 1 year)

• Phase 2: Transitioning from words to speech 9 1 to 2 years)

• Phase 3: The growth of the inventory (2 to 5 years)

• Phase 4: Mastery of speech and literacy (5+ years)

Vowel production

During the first year, vowel production dominates, maybe the lax vowels //, front-low and mid central

From word to segment

• It has been suggested that the earliest units the child targets for production are whole-word patterns rather than segments or even syllables• Children try to produce whole words• Prosody matches that of whole words• Some words or parts of words occur in advanced forms

• Some reorganization of sound patterns of words that are produced in advanced forms, and then are changed to the child’s overall patterns• Progressive idioms • Apparent regression• Creative strategies• Phonological selectivity or avoidance patterns

Components of typical speech acquisition

• Intelligibility - “Single most practical measurement of oral communication competence”

• Comparison of speech sounds with adult target• Acquired sounds: consonants, consonant clusters, vowels• Percent correct (PCC)• Phonological patterns/processes

• Abilities of the child (without comparison to adults)• Phonetic inventories: consonants, consonant clusters, vowels• Syllable structure

• Prosody• Metalinguistic/phonological awareness skills

Research and development

• Method of speech sampling• Diary Studies• Large-Group Cross Sectional Studies• Combined Data-Collection Procedures

• Issues• Socioeconomic differences• Number of subjects being studied• Defining mastery

• Mastery of Production

• The age at which particular phoneme is produced with some degree of accuracy (75-100 %)

• Customary Production

• Age at which a particular phoneme is produced with greater than 50 % accuracy, in at least two word positions.