Speech and Language Devlopment Midterm

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The Territory of Language

Origin of Language

• All social animals have some form of communication

• Language is plainly, obviously, uniquely human

• It is unknown how language actually evolved in the human species

• Numerous theories have arised

~Bow-wow, yo-he-ho theories

• Language may have emerged when humans experienced evolutionary changes to their larynx and cognitive abilities

~ ~100,000 years ago

• Others have proposed that humans have an innate capacity for language

• Short answer: we don’t know

• There are 6-7,000 languages spoken in modern day

• Death of languages is common

~Indigenous populations are slowly dying out

• Death of language = death of culture

Defining Key Terms

• ‘Speech,’ ‘language,’ and ‘communication’ are NOT interchangeable terms

~Speech and language denote different aspects of development

• Speech: refers to the spoken means of communicating that requires fine neuromuscular control and coordination

• Speech = a physical act; noise

• Every language in the world contains individual speech sounds, or phonemes

• In addition, ‘speech’ involves other aspects that help convey our message, such as rate, prosody, and vocal quality

• Speech sounds are meaningless unless regularity is added

• Language: a socially shared code or system for representing concepts

~Language exists by virtue of social use

• Every language in the world has its own set of unique symbols and rules for symbol combinations

• An oral code is not mandatory for a language to exist (ex. Sanskrit)

Properties of Language

#1: Language is a social tool

• Code of transmission among shared users

• Language is not essential for communication, but communication is essential for language

#2: Language is a rule-governed system

• Non-arbitrary arrangement of words and sounds

• We adhere to the rules of language, even if we can’t expressly articulate them

#3: Language is generative

• Infinite number of sentences can be said, even with immature users

• Both speech and language are parts of a larger process called communication

• Communication: the exchange of information, ideas, needs, and desires between two or more individuals

• A very complex process

~Speech

~Language

~Hearing

~Memory

~Knowledge of cultural norms

~Situational variables

~Etc.

• Despite its complexity, communication is easy for most individuals

~Success with communicating = communicative competence

• An individual must be effective with the linguistic features of communication (speech and language) to have communicative competence

• Communication is also made up of extralinguistic features

~Paralinguistc codes

~Nonlingusic cues

~Metalingustics characteristics

• Paralinguistic codes: vocal and nonvocal cues superimposed on the linguistic code to alter meaning and/or convey emphasis/attitude/emotion

~Intonation

~Stress

~Rate of speaking

~Pause and hesitation

• Nonlinguistic cues: coding devices that contribute to communication but are not part of the act of speaking

~Facial expressions

~Eye contact

~Physical proximity

~Gestures

~Posture

• Culturally bound

• Metalinguistics: the consideration of language in the abstract

• The ability to talk about language, analyze it, think about it, judge it, and see it as an entity separate from its content or context

• Important for reading and writing development

Components of Language

Form

• Form: the shape or construction of language…grammar

Three major components

• Syntax: organizational rules for specifying word order and sentence organization

• Morphology: rules governing change in meaning at the world level

~Study of the structure of words

~Morpheme: smallest unit of meaning; indivisible without changing meaning

~Free morphemes (happy; dog), bound morphemes (-ier; un-; -s)

• Phonology: the sound system of a language

~Phonemes: the smallest linguistic unit of sound (43 in American English)

~Phonotactic rules: rules governing how sounds can go together in a language

~/st, not /sg/; /pl/ not /pm/; /-ing/, nit /-ifr/

Content

• Semantics: meaning of words and word relationships

• Word knowledge forms your personal mental dictionary, or lexicon

~Our world knowledge affects our word knowledge

• Each word in our vocabulary contains semantic features and selection restrictions

• Pragmatics: social use of language

• The way language is used to communicate rather than form or meaning of what is said 

~What is the reason the person is speaking? Give direction? Make request? Provide statement? Attempt to gain knowledge?

• Conversations are governed by a set of pragmatic rules

~Taking turns

~Maintaining a topic

~Making relevant contributions

~Listener characteristics: age, gender, social status, role

• In White, middle-class cultures in the U.S., the following pragmatic forms are generally accepted:
  ~One person speaks at a time

~Speakers are not interrupted

~Eye contact is maintained

~Each person contributes to the conversation 

~Topic is maintained

~Listener demonstrates comprehension through feedback

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Theories of Language Development

Theories

• Provide a framework for research

• Help explain the language development process

• Help guide intervention and treatment

• Many theories, often compete for overarching acceptance in the filed

• In reality portions of each theory are used to explain different aspects of language (each holds “nuggets” of truth)

#1: Nativist Approach

• Pioneered by Noam Chomsky in the 1960s at MIT

• Children are born with innate rules or principles related to the structure of language

• Something innate or inborn guides children’s language development

• Language development is too complex a process to not be aided by knowledge of innate linguistic patterns

• Children likely have a language acquisition device (LAD) in their brains

~Allows for a natural propensity with which to organize the spoken language we hear

• Since language is a universal human trait, there must be similarities across all languages, and these “rules” are present at birth

• Children then use their innate rules in the LADs to figure out the specific rules of the language to which they are exposed

Advantages

• Helps explain rapidness of language acquisition

~Children do not require explicit instruction to learn language

• Helps explain creativity of language acquisition

~“More bounce” “All gone milk” - children likely have never heard an adult say that before

• Helps explain how children in impoverished language environments still learn language 

Shortcomings

• Much of early language is indeed a memorized whole

~“Thank you” “You’re welcome”

• Minimizes the role of the environment and caregiver input

• No neurological basis for the LAD

• Limited application to atypical development

Nativist approach to treatment: Model grammatically correct sentences, provide rich linguistic input. trust the process

#2: Interactionist Approach

• Big names: Michael Tomasello, Lev Vygotsky

• Language develops through meaningful interactions with caregivers, peers, and others

~Social interaction is essential because it provides the context where children can practice and refine their language skills

• Emphasizes both genetic and environmental influences

~Children are born able to learn language but need exposure to language to fully develop it

~Emphasizes children as pattern finders

~Child hears person + action (e.g., “Mommy eat”) structure often and recognizes the pattern

~Child then generalizes person + action in other contexts (e.g., “Daddy go” “Me run”)

Rules become more abstract over time (e.g., person + action + object - “Mommy eats a cookie”)

• Learning occurs best when there is participation from the learner in natural situations

Advantages

• Balances the nature vs. nurture argument

• Highlights the importance of social interaction

Shortcomings

• Under-emphasizes the role of biology

• Does not address why impairments and delays exist if caregivers provide sufficient input

• Cultural bias?

Interactionist approach to treatment: Teach caregivers to model language during daily routines, engage the child in interactive activities that require turn-taking and joint attention (e.g., shared book reading, pretend play), respond to and expand on the child’s communicative attempts

Learning Theories

Theory #3a: Behaviorism

• B.F. Skinner

• Children learn language through reinforcement and punishment

~Responses to a language behavior can strengthen or weaken the behavior

~For example, a child says “more” while eating a cookie, and the child receives more of the cookie

~Or, a parent praises a child for imitating their word

~Or, a parent ignores a child for an incorrect production

• Observable actions, not internal processes

Advantages

• Practical applications

• Highlights the role of interaction

Shortcomings

• Limitation explanation of grammar acquisition

• Ignores cognitive processes, such as memory and attention

• Caregivers don’t have to reinforce language in order for it to be acquired

Behaviorism approach to treatment: Reinforce desired language behaviors, focus on modeling and imitation, correcting incorrect responses and avoiding reinforcement of errors

Theory #3b: Cognitivist Theory

• Jean Piaget

• Language learning is governed by internal processes, not just external circumstances

~Learner plays an active role

• As a child tries to process new information, they compare to what they already know and store it in their memory

~Prior knowledge! Memory! Understanding patterns! All important

• Children are constantly looking for patterns, rules, and meanings

~A child noticing that -ed is used for past tense verbs, then applying it to walked, goed

• Children are also building schemas and constantly determining if a new concept should be assimilated into a current schema or accommodated into a new schema

~“Dog” schema includes poodles and terriers, but not wolves and foxes

Advantages

• Acknowledges the importance of cognitive processes in language development

• Child plays an active role

Shortcomings

• Reduces the role of interaction and social learning

• A bit abstract

Cognitivist approach to treatment: Asking open-ended questions to encourage talking, creating activities that link language with cognitive processes - grouping animals by category

Theory #3c: Social Constructivist

• Vygotsky

• Knowledge is “constructed” within social contexts through interactions with knowledged individuals 

• Language is primarily acquired socially and is not possible alone

• Zone of proximal development: the difference between what the learner can do without help and what they can do with guidance and encouragement from knowledgeable others

• Scaffolding: providing temporary support to help children learn new skills

• Explains why a child’s language is similar to but often less mature than that of the adult partner

• When children imitate others or attempt to use language that mirrors that of an adult, they develop words and larger units of language that enable them to navigate these interactions

Advantages

• Highlights importance of social context

• Aligns with evidence that rich language interactions promote language development in children

Shortcomings

• Under-emphasizes innate abilities

• Relies too heavily in caregivers/parents

Social constructivist approach to treatment: Rich, meaningful language interactions, select tasks within the ZPD, appropriate scaffolding and assistance, then gradually reducing

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Neurological Bases of Language

Central Nervous System

• Central nervous system (CNS): composed of two parts: the brain and spinal cord

• Peripheral nervous system (PNS) includes the motor and sensory pathways that branch from the brain and spinal cord

• Messages within the CNS are communicated though neurons, or nerve cells (100 billion of them)

• Three main components of a neuron:

~Cell body

~Axon

~Dendirtes

• Chemical-electrical impulses “jump” between neurons via the synapse

• CNS is encased in bone and membranous layers of meninges

• Spinal cord connects to the brain via the brainstem

~Midbrain

~Pons

~Medulle

~Responsible for involuntary functions like breathing, heart rate

• Cerebellum: “little brain”

• Contains two hemispheres

• Most of its functions are motor-related, such as coordinating fine muscle movements and maintaining muscle tone

• Plays a role in processing and higher-level cognitive functions, particularly in the posterior lobe

~Exectutive functions

~Memory

~Attention

• Sitting atop the spinal cord and brainstem is the cerebrum

• Cerebrum: consists of the cortex and subcortical structures

~Gray matter = cortex, mostly cell bodies

~White matter = subcortical structures, mostly axons

• The cerebrum contains right and left hemispheres with contralateral motor and sensory functions

• Distribution of specialized functions (ex. language) is usually lateralized to one hemisphere

• Both the right and left hemisphere play a role in language processing

Right Hemisphere

How language is said

Paralinguistic information

• Speech prosody and affect

• Metaphorical language

• Music/laughter

• Emotional language

• Humor

Left Hemisphere

What is said

Linguistic information

• Comprehension

• Production

• Written language

• 98% of the population is left hemisphere-dominant for language

• Research suggests that left hemisphere specialization results in more advanced language during the early years

• The brain connects nerve tracts for communication

Three classifications

• Commissural fibers

~Between right and left hemispheres

~Corpus callosum

• Association fibers

~Within a hemisphere

~Arcuate fasciculus

~Between Broca’s and Wenicke’s areas

• Projection fibers

~Brain to subcortical structures and below

• Four lobes on each hemisphere of the brain, each with a different primary responsibility

Frontal Lobe (25-40%)

• Primary motor cortex

• The largest lobe of the cerebral cortex

• Responsible for a range of functions including motor control, personality, behavior, working memory, and decision-making (EXECUTIVE FUNCTIONS)

• Contains Broca’s area

~Production and coordination of speech

Parietal Lobe (19%)

• Primary sensory cortex

• Sense of touch, proprioception; integrating information from our senses to make sense of our environment; left/right, temperature, pain

Temporal Lobe (20%)

• Primary auditory cortex

• Responsible for memory, language comprehension, hearing

• Contains Wernicke’s area

~Comprehension of written and spoken language

Occipital Lobe (10-18%)

• Primary visual cortex

• Vision and visual perception

• At birth the brain weighs approx. 25% of its fully developed weight

• Rapid growth and myelination occurs in the first years of life

~Melination: sheathing process of connections between neurons

~Higher in girls than boys?

Language Centers

• Complicated, interconnected processes

• Recent knowledge has been informed by advances to brain imaging

~Both hemispheres

~Largely concentrated in the frontal and temporal lobes

~No evidence of a single processing center

• It is not linear

• Language comprehension

~Auditory processing + language decoding → attending to information + underlying meaning

1. Most auditory signals received by the brainstem and sent to the auditory area (Heschl’s area)

2. Linguistic information is sent to the left temporal lobe and paralinguistic information to the right temporal lobe

3. Linguistic information must be remembered in order to be processed, called auditory woking memory, this likely occurs near Broca’s area in the left frontal lobe

4. Linguistic information (phonological, syntactic, and semantic) is then processes near Wernicke’s area in the left temporal lobe

5. The right hemisphere aids in the processing, particularly for whole units (ex. What’s up? How are you?), abstract words (ex. Beauty, wisdom), and additional semantic processing

• The processing of linguistic information happens in an instant

• How quickly, and which areas of the brain are involved, will vary depending on the complexity of the sentence

• Language production largely relies on the same set of areas as comprehension

1. Conceptual basis forms in one of the areas responsible for memory

2. Structure of the message occurs in Werinicke’s area

3. The message is transmission via the arcuate fasciculus to Broca’s area, which helps program the movements for speech

4. Signals are sent to the motor cortex to activate speech muscles

Additional Processes

• Processing language involves more than just comprehension and production

Attention

• Cannot process all incoming information

• Must allocate and sustain attention to language

Working Memory

• Holding a message “online” while processing occurs

• As young children learn language, they rely on WM to hold sentences during analysis to discover the linguistic properties

• These skills in young children are strongly related to learning new words, literacy skills, math, comprehension

Long-Term Memory

• Explicit/declarative memory: knowledge of facts and events

• Implicit/procedural memory: knowledge of how to do something 

• Both are important for language

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The Infant Years: Sensation, Perception, & Motor Bases of Speech

Important milestones will be highlighted in orange

Neurological Development

• The development of the bases for communication begins in utero

~Brain begins developing 18 days post-conception

~One of the slowest organs to mature

• All of the brain’s neurons have been generated by month six of pregnancy

~Organization is lacking; no myelination and limited communication between cells

• Physical brain is under genetic control; however, development is altered by experiences with the outside environment

• Earliest areas of the brain to develop are the primary motor and sensory areas and brainstem

• After birth there is rapid growth in the cerebellum and frontal lobe (coordinated movement), as well as the visual cortex

• Months 6-12, areas responsible for memory and thought begin to mature

• Process of total brain maturation continues well into adulthood, though the areas responsible for language are mostly developed by late preschool 

Development of Sensation and Perception

• Sensation: the ability to register sensory information

• The ability to perceive sensory information begins in utero, with touch and hearing being the first sensations at approx. 8 weeks

~Middle and inner ears are fully developed at 20 weeks

• Smell also develops in utero, with infants demonstrating a preference for the scent of their mother post-birth

• Although sensory capabilities are stable with birth, there is a HUGE change in environment

~These sensory experiences “nourish” the mind and contribute to brain development

• Moderate levels of stimulation are most preferable for newborns

• An infant’s attention is initially dictated by their internal state but eventually shift to external sources

~Infants are better able to regulate and maintain a stable internal condition, allowing them to focus more on their environment

Sensation

• Infants eventually learn to habituate around 2 months of age

~Habituation: gradually paying less attention to stimuli that are presented repeatedly

~Helps an infant not respond to each and every stimulus present in their environment

~Earllist form of infant memory and a marker of cognitive development

Perception: Visual

• Perception: using both sensory information and prior knowledge to make sense of incoming stimuli

• Visual perception skills are fair in infants…mostly blurry images (8 inches)

~Prefer highly contrastive materials (hence, black and white toys)

• Infants quickly learn to direct their attention to faces

~Recognize caregiver’s face within a few days of birth

~Discriminate between faces by 3 months

~Prefer “typical” faces

Perception: Auditory

• Because fetuses can hear in utero, newborns tend to prefer their mother’s voice (not the father’s)

• Unique finesse for voices in general over environmental sounds

• Infants as young as two months can discriminate various intensity levels, frequencies, and even consonant contrasts

~High amplitude sucking studies

• When infants hear speech over and over, neurons in the auditory system fire and are “assigned” different phonemes

~Similaries and differences are noted

~Clusters of neurons will fire when specific speech sounds are heard

• This helps explain how, despite infants being born with the ability to acquire any language, they lose their ability to discriminate between phonemes NOT in their language by 8-10 months of age

• Infants spend much of their first year of life losing their ability to perceive constants not used in speech around them

The ability to perceive other aspects of speech develops in the first year

• Phonemes: at birth

• Sound patterns for words (ex. own name): 5 months

• Prosody: 8-10 months

• Phonotactic probabilities: 8-10 months

~The likelihood that certain sounds will go together

~High probability combinations (/br/, /-ing/) likely indicate words

~Low probability combinations (/vt/, /fh/) likely indicate word or syllable boundaries

~Correlated with vocabulary size at age 2

Motor Development and Speech

Motor Development for Speech

• Producing speech is a fantastically complex motoric process, taking years to develop and mature

• Newborns produce two main types of sounds:

~Reflexive: fussing, crying, lengthy vowel-like sounds on exhalation

~Vegetative sounds: burping, sneezing, brief vowel/consonant-like sounds on inhalation and exhalation

• Eventually, they produce sounds called quasi-resonant nuclei (QRN)

~Nasalized, vowel-like sounds

~Largely stem from the lack of motor control + immature vocal tract

• By 2-3 months of age, infants will produce vocalizations in response to caregiver interactions

~Gooing or cooing: QRN-esque but with some back consonant production (/g/, /k/, /h/) 

~Back-and-forth “conversations” are possible

• Approx. 4 months, infants begin to laugh

• Around 5 months, consonant-vowel (CV) combinations replace QRNs and cooing- babbling begins

~Rarely VC combinations

• Babbles sounds are fully resonant nuclei (FRN) and have more true vowel-like qualities

~Larger oral cavity

~Greater motor control over the lips and tongue 

~/m/, /b/, /p/, and /w/ dominate early babbling

~”ee”, “ou” and “aaa” common vowels

• Can imitate tone and pitch of others

• Eventually, babbling begins to more closely resemble adult speech

• CV becomes CV-CV-CV (/ma-ma-ma/): reduplicated babbling

~Initially self-stimulating but eventually used in back-and-forth interactions with adults

~Stop and nasal sounds are most common: /p/, /b/, /k/, /g/, /d/, /t/, /m/, /n/

~The frequency of various phonemes in a child’s babbling influences the words that a child first begins to say

• Aren’t necessarily producing reduplicated babbling with meaning; however, infants learn that babbling gain adults’ attention

• By 8-10 months, variegated babbling emerges

~CV-CV-CV becomes C1V1-C2V2-C3V3 (/mi-ba-gou/) or C1V1-C2V1-C3V1 (/ma-ba-ga/)

~Successive syllables are not identical

• Infants expand their consonant repertoire, and variegated babbling sounds similar in tone and prosody to adult speech

• Less self-stimulatory, more purposeful

• An infant’s babbling eventually mirror the prosodic pattern of the language to which they are exposed

• Jargon emerges at approx. 10 months

~Long strings of unintelligible sounds with adultlike prosody and intonation

~May sound like questions, commands, exclamations

• Before first words emerge around 12 months, infants often acquire an number of phonetically consistent forms (PCFs), which function as “words” for the infant

~Consistent prosodic and phonetic pattern used to represent a single referent

~Occur with pauses that clearly mark boundaries

~“Wowow” to refer to the family pet, “ga” for car, “vroom” for car

~Usually accompany events or actions in the environment

• PCFs are important because the infant is learning the value of adopting a stable pronunciation for communicating

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The Infant Years: Social & Communicative Bases of Speech

Important milestones will be highlighted in orange

• Infants develop the essential skills for learning language within dyadic infant-caregiver interactions

• It is important to examine the behavior of both the caregiver and the infant in their early interactions that facilitate speech and language development

Development of Communication

1 Month

• Newborns have a small set of behaviors to help them communicate 

~Eye contact – utmost importance

~State regulation and sleep-wake cycles

~Head movements

• Begin to participate in basic interactional sequences

• Social smile: smiling in response to an external social stimulus (3-6 weeks)

2 Months

• Previously described skills are increasing

• Infants begin to associate specific people with specific actions

~Infants will begin a sucking motion when seeing their mother

• Increases in visual memory – lots of toys/stimuli needed…rapid boredom 

• Cooing begins at this age

3 Months

• Big changes occur around this time

• More recognition of caregivers, more social smiling, more people watching

• Infants can maintain more consistent internal states

• More intense infant-caregiver bonding occurs

~Levels of maternal playfulness and sensitivity at 3 months predict an infant’s attachment style at 9 months

• Infants learn the stimulus-response sequence

~Creating a signal, such as a cry, will elicit a predictable response

~Infants learn that they can now change or control the environment with their behaviors

• Immediate positive parental responsiveness increases a child’s motivation to communicate

4-6 Months

• Greater imitation from the infant

~Gestures: the appearance of gestures signals a developing cognitive ability to plan and to coordinate that plan to achieve a desired goal

~Facial expressions

~Prosody/intonation

~Nonspeech sounds

• Rituals and game play

• Face-to-face play helps infants learn and mirror facial expressions

• Babbling begins at this age

• Vocalizations signal contentment, dissatisfaction

• By 6 months of age, infants have learned that their vocalizations have social value

• Interest in toys and objects increases

~Prior to this period, an infant is not greatly attracted to objects unless they are noise-producing or made mobile and lively by an adult

~Better eye-hand coordination

~Moving forward, interactions go from infant-parent to infant-parent-object

8-12 Months

• Intentionality grows immensely during this period

~Learning to communicate wants, needs, and intentions more clearly

~Goal-directed behavior

~Considering your audience

• At 8-9 months, intentionality is mostly expresses via gesture

~Ex. Touching mother, establishing eye contact, and pointing toward a toy

• Increased interest in manipulating object and demonstrating knowledge of what common objects do

~Ex. Phone to ear, spoon to mouth – considered a primitive form of naming

• Protoimperative gestures are requests for objects 

~The earlier infants produce imperative gestures the more frequently their mothers talk about their infants’ own states, using words such as want, try, and need

• Protodeclarative gestures include pointing and showing

~Goal of maintaining joint or shared attending

~Does not occur when not in the presence of an adult

• Initially, gestures appear without vocalizations, but the two are gradually paired, particularly with PCFs

~PCFs are a transition to wrds in a highly creative developmental period

• The development of pointing is particularly important

~Cross-culture development; likely universal in infants

12+ Months

• There is a shift from the intentional phase of communication to the symbolic stage 

~Begins with the first true meaningful word

• The child’s intent becomes encoded in words that are used with or without gestures

~Accomplishes the intentions previously filled by gestures alone

Maternal Communication Behaviors

• The foundation for infant–caregiver face-to-face exchanges is in the modifications made by the adult to accommodate a child

• Within the exchange, mothers perform infant-elicited social behaviors, such as exaggerated facial expressions, body movements, positioning, timing, touching, prolonged gaze, and modified speech

~These modifications also occur in the behavior of other adults and older children

~Neither prior experience with infants nor prior learning seems to explain this adult behavior

• Why does this happen? → Simply, babies are cute

• One major infant-elicited social behavior is infant-directed speech (IDS)

~Also called “motherese” or “parentese”

• Charactered by short utterance length, simple syntax, and use of a small core vocabulary

• Use of paralinguistic variations, such as intonation and pause

• Employing more frequent facial expressions and gestures and an overall higher pitch

• Maternal speech prior to 6 months contains fewer than 3 morphemes per utterance, expanding to about 3.5 or more morphemes at 6 months

~Average adult speech = 8 morphemes

• In general, mothers who use more short sentences when their children are 9 months of age have toddlers with better receptive language abilities at 18 months

• Mothers also use a considerable number of questions and greetings with their infants

~Enable a mother to treat any infant response as a conversational turn

~Sneeze, smiles, coos, and laugh may be given a meaningful reply

• More than 20% of maternal utterances are greetings such as hi  and bye-bye or acknowledgments such as sure, uh-huh,  and yeah

What purpose do you think IDS serves?

1. Captures and maintains an infant’s attention

2. Optimal level of training for language learning

3. Promotes infant responsiveness and conversational turns

4. Facilitates infant learning of phonological regularities of the native language

5. Emotional bonding

Infant-Caregiver Joint Behaviors

• Joint behaviors are of particular interest for language development

~Joint reference

~Joint action

~Turn-taking

~Protoconversations

• These behaviors are influenced by child temperament

~Positive factors, such as orienting toward a parent, easy soothability, and frequent smiling and laughter at 6 to 12 months of age, are related to better receptive vocabulary at 21 months

~In contrast, high emotionality in children, such as extreme tantrums, is related to poorer receptive vocabulary skills

~Significant stress on parent-child interactions; stressed moms = less responsiveness

• One of the most common sequence of infant-caregiver joint behaviors is joint reference

~Reference = ability to note the presence of an entity/object

~Joint reference = two or more individuals share a common focus on one entity/object

• Gradual mastery of joint attention occurs within the first six months of life

~An infant learns to look at objects and events in the environment in tandem with mother and to maintain eye contact

~Mother: “Oh look!” Shakes rattle + waits for the child to respond

• These skills are foundational to vocabulary development via naming

~Infants are able to associate names with their referents prior to developing the ability to produce names meaningfully

• Another common sequence of infant-caregiver joint behaviors is joint action

~Shared action sequences between the caregiver and the child, often routines and shared action body games

• Provide structure with which to analyze language

~Ex. Peek-a-boo, “I’m gonna get you”

~Within these exchange games, an infant learns to shift roles, take turns, and coordinate signaling and acting

• Joint behaviors contain the all-important element of turn-taking, resulting in protoconversations even in very young children

• For example, mothers and their 3-month-old infants exhibit initiation, mutual orientation, greeting, a play dialogue, and disengagement

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The Toddler Years: First Words

Important milestones will be highlighted in orange

First Words

Toddler language development

• Once a child reaches approx. one year of age, it is common to say “language development” instead of “speech development”

To be considered a true first word, it must have the following features:

1. Phonetic relationship with the adult word

2. Use the word consistently 

3. Must occur in the presence of a referent, thus implying an underlying concept or meaning

• Using these criteria, a babbled “dada” would not qualify if there is no referent

• Likewise, PCFs that do not approximate recognizable adult words don’t qualify as words

• The emergence of first words or verbalizations does not signal the end of babbling, jargon, PCFs, and gestures

~Words emerge slowly 

• Common first words? Anything in the toddler’s “world”

~Toys

~People

~Pets

~Food

~Rejections (“no”) or greetings (“bye bye”)

• There is a strong relationship between first words and the frequency of the caregiver's use of these words

• Each toddler has their own lexicon, or personal dictionary, with words that reflect the child’s environment 

• Vast majority contain CV or CVCV structure

• Three or fewer sounds

• Front consonants such as /p/, /b/, /d/, /t/, /w/, and /n/, and back consonants, such as /g/, /k/, and /h/, predominate – stop sounds in particular

~No consonant clusters, such as /tr/, /sl/, or /str/, appear – too difficult

• Not explained by the frequency with which the sounds occur in English; rather, predicted by ease of production and perception

A number of factors influence which words toddlers will acquire first

1. Grammatical class

2. Frequency of input from adults

3. Phonology of the word

• Children’s early one-word utterances often represent holophrases

~Learning whole adult utterances that represent various communicative purposes

~For example, “mommy” could mean: that’s my mommy, mommy come here, I need help mommy

• One-word utterances may often sound like two-word utterances but are in fact a single learned entity

~“Wassat”

~“Bye-bye”

~“Thank you”

~“I love you”

~“Lemme see”

~Over-relience on memorized formulas may disadvantage children – lack of analysis

• Growth of the lexicon is slow from months 12-18

~Children are often still relying on gestures and pairing gestures with single words to convey meaning

• At the center of a child’s lexicon is a small core of high-usage words

• Approx. 50 words at 18 months, mostly nouns (60%)

~Receptive understanding is generally 4x that

~Remember: receptive language is always greater than expressive language

• Plateaus are common

• Wide range of normal

• Lexical growth rate accelerates as a child nears the 50-word mark

• The second half of the second year is one of tremendous vocabulary expansion

~“Vocabulary spurt” between 18-24 months – 200-300 words

• Significant individual variation

~Female children seem to begin to acquire words earlier and have a faster initial trajectory

• 18-month-olds produce an average of two communicative acts per minute to request objects or actions, establish joint attention, or engage in social interaction

• Between 18 and 24 months, children significantly increase their frequency of communication, both verbally and nonverbally, and move toward more frequent verbal expressions of intent

~24 months = 5-7 communicative acts per minute

• Towards the end of the first year verbs become more prominent

• Verbs may be harder than nouns to acquire

~Abstract; hard to determine in the physical environment

~Old man dancing vs. a ballerina dancing

~Short duration of occurrence – throw, kick

~May not be happening in the present time

~We are going to the park larer. You will play with Simon.

How are toddlers learning words so fast?!

• Children form a link between a particular referent ad a new name is called fast mapping

~Fast mapping = rapid word learning

~18 month olds are capable of learning new words with as few as three exposures

• Children’s meanings encompass a small portion of the fuller adult definition

~Parent: “No touch – hot!” regarding oven; Child: “No touch – hot!” regarding petting the cat

• More in-depth learning occurs subsequent to the initial mapping as a child is exposed repeatedly to new instances of a word

~Gradually the word is freed from aspects of the initial context

• In the process of refining meanings, children from hypotheses about underlying concepts and extend current meanings to include new examples

~Overly restricted meanings are called underextensions

~“Cup” only means the child’s cup and no other cup

~Overly broad meanings are called overextensions

~Calling every dog “Fido” because the child’s dog’s name is Fido

~Up to ⅓ of the child’s first 75 words are overextended

• Over time words develop a “confirmed core” meaning 

Pragmatic Functions of the Early Language

1. Labeling the existence of an object

2. Requesting the recurrence of objects or events, using words such as more and ’gain

3. Demanding objects of events

4. Describing changing events involving objects by up, down, on, off, in, out, open, and close, or the actions of others with ords such as eat, kick, ride, and fall

5. Commenting on the location of objects and people with wrds such as bed, car, and outside

6. Asking some basic questions such as What?, What that?, and Where mommy?

7. Attributing a property to an object such as big, hot and dirty

8. Protesting/rejecting an undesired action

9. Social acts such as hi, bye, and thank you

Pragmatic functions vary with age

• 15 months: naming/labeling predominant

• 18 months: demands, protests

• 24 months: requesting, questioning, unsolicited statements or declarations, verbal accompaniments to play (Whee!), and expressions of states and attitudes (I tired)

Lexicon Analysis

• It is important to describe the universe of a child’s speech-making and word-making abilities when determining if they have typically developing language

• More than just counting the number of words in a child’s vocabulary

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The Toddler Years: Multi-word Combinations

Important milestones will be highlighted in orange

Multi-word Combinations

• As toddlers approach 18 months they increase their combination of gesture and vocalizations

~*Points* “ball”  – most common

~*waves* “bye-bye”

~*Shakes head* “no”

• Shortly after toddlers begin to combine words into short utterances

~Single words, jargon, and babbling still occur

• By 24-36 months old, 98% of toddlers produce two-word sentences, 90% produce three-word sentences, and 84% produce four-word sentences

• Remember: huge vocabulary sport between 18-24 months

What helps this transition from one to two words occur?

• Greater expressive vocabulary

~By 24 months old, mean vocabulary size is ~312 words

~By 30 months old, ~546 words

• Caregivers often elicit successive single word utterances during conversation, modeling early word combinations

• Toddler’s earliest combinations are a combination of words they already have in their lexicon

• Multiword utterances come in three varieties that describe a developmental order:
  ~Word combinations

~Pivot schemas

~Item-based constructions

Word Combinations

• Consists of roughly equivalent words that divide an experience into multiple units

• Two successive one-word utterances

~Doggy bed

~Stove hot

~Daddy nice

~Wave bye-bye

Pivot Schemas

• Two-word utterances in which one word “structures” the utterance by determining the intent of the utterance as a whole

• Often contain one anchor word + _______ that fills in the slot

~More + juice/cookie/story

~Want + juice/cookie/story

~All done + juice/cookie/story

• Children will use pivot schemas with novel words, showing that they have some rudimentary grammatical knowledge

Item-based Constructions

• Based on word-order rules and often contain morphological markers (ex. plural -s, present progressive -ing)

~Baby’s bottle

~More in cup

~Daddy driving

~Baby eat

• Demonstrate a more developed understanding of grammar

• More generative compared to pivot schemas

Review of Speech Sounds

• Consonants are produced with some degree of constriction in the oral, nasal, and/or pharyngeal cavities

• Three major classifications:

~Place: where the sound is produced

~Manner: how the sound is produced

~Voice: whether the voice is on or off

Place of Production

• Bilabial: /p/, /b/, /m/

• Labiodental: /f/, /v/

• Interdental: /th/

• Alveolar: /t/, /d/, /s/, /z/, /l/, /n/

• Palatal: /sh/, /zh/, /ch/, /j/, /y/, /r/

• Velar: /k/, /g/, /ng/

• Glottal: /h/

Manner of Production

• Stops: /p/, /b/, /t/, /d/, /k/, /g/

~Stopping the airflow, then a quick burst

• Fricatives: /s/, /z/, /th/, /f/, /v/, /sg/, /zh/

~Noisy turbulence at the place of articulation

• Nasals: /n/, /m/, /ng/

~Airflow from the nasal cavity

• Glides/liquids: /y/, /w/, /l/, /r/

~Glides are “semi vowels”

• Affricates: /ch/, /j/

~Combination of a stop and a fricative

Many consonants have a “pair” that is just a voiced or voiceless version of the other:

• /b/ and /p/

• /t/ and /d/

• /k/ and /g/

• /th/ and /th/

• /ch/ and /j/

• /s/ and /z/

• /f/ and /v/

• /sh/ and /zh/

• Children tend to avoid words that contain sounds they cannot pronounce

Sounds that tend to be acquired first:

• Place: bilabial, alveolars, velars

• Manner: stops, nasals

Multi-word Combinations

• Children also tend to avoid words that contain a syllable shape they haven’t acquired yet

• Must first develop a “phonological template,” then new vocabulary words can be added

~Remember → CV, CVCV shapes are acquired first

~CVC often comes next

~Bike, car, dog, cat

~Likely NOT cash, dark, bath

Phonological Benchmarks for Toddlers with Typical Development

24 months:

• Sound  (consonants): voiced and voiceless stops; nasals; glides; one or two fricatives

• Word/syllable shapes: CV, CVC, CVCV, CVCVC, come clusters

• Accuracy (PCC): 70%

• Common error patterns: fricatives/affricates replaced by stops, liquids replaced by glides

• Intelligibility: 50%

• Lexicon size: 250-300 words

Review of Speech Sounds

• As children’s vocabulary expands the presence of phonological processes become more apparent

~Systematic procedures used by children to make adult words pronounceable

~Enable children to produce an approximation of an adult model

• Children’s phonological processes exhibit tremendous individual variation

~Often leaves adults having to figure out the target word

~Results in reduced intelligibility of toddler speech

Examples:

• Reduplication (CVCV)

~Water becomes wawa

~Mommy becomes mama

~Baby becomes bebie

• Assimilation

~Dog becomes gog

~Candy becomes cacie

• CVCV constructions

~Horse becomes hawsie

~Duck becomes ducky

• Open syllables

~Blanket becomes bakie

~Bottle becomes baba

• Consonant cluster reduction

~Stop becomes top

~Tree becomes tee

• Weak syllable deletion

~Banana becomes nana

~Spaghetti becomes ghetti