• Humans use symbols to represent our thoughts, feelings, knowledge, and to communicate to others.

Language Development

• By 5 years of age, most children have mastered the basic structure of their native language(s).

• Language use requires comprehension (understanding what others say, sign or write) and production (the process of speaking, signing, or writing).

• Infants and young children understand much more than they can say.

The Components of Language

• The system of language is generative - meaning it is a system in which a finite set of words can be combined to generate an infinite number of sentences.

• This system lets us understand sentences we have never heard before, because they make use of familiar words and grammatical structures.

• Speech is composed of units of sound called phonemes,and a change in phoneme changes the meaning of a word (ex. rake vs lake).

• The smallest units of meaning are called morphemes, and these alone, or in combination, constitute words (dog → 1 morpheme, dogs → 2 morphemes (dog, -s)).

• Syntax is the rules specifying how words from different categories (nouns, verbs, adjectives, etc.) can be combined, and the order in which words can appear in a sentence is crucial to the meaning. (ex. Lila ate the lobster vs the lobster ate Lila.)

• Pragmatics refer to the understanding of how language is typically used in a specific cultural context, and they are necessary to go beyond the words to understand what the speaker is really trying to communicate using context and emotional tone.

What Is Required for Language

A Human Brain

• Language is a species-specific behavior and it is species-universal (only humans acquire language and it is achieved by children across the world).

  • No other animals naturally develop anything as complex and general as the human language, but they can communicate with each other through specific calls and such, but this is limited in scope.

• Apes can learn sign-language and combine symbols, but whether syntax applies is unclear.

• There are several well-documented cases of nonprimate animals that have learned to respond to spoken languages.

Brain-language lateralization

• Language is primarily controlled by the left hemisphere, and this emerges very early in life.

• Lifelong singers process sign languages in left-lateralized language centers in the brain, while non-singers can’t, which is an example of experience-dependent plasticity.

  • This shows that left-hemisphere brain regions are used for signed as well as spoken languages.

Sensitive period for language development

• Early years are a sensitive period during which languages are learned relatively easily (this period ends sometime between 5 years old and puberty).

  • After this, learning a langauge becomes less successful.

• Adults are more likely to suffer permanent language impairment from brain damage than children because other ares of the young brain can take over language functions.

• Adults who learned a 2nd language after puberty use different neural mechanisms to process langauge than adults who learned their 2nd language from infancy.

• Individuals who learned ASL first develop a better understanding of the grammar of ASL than those who acquired it as a first language as teens or adults.

  • This shows that sensitive periods in language acquisition have clear practical implications and in this scenario, deaf children should be exposed to sign language as early as possible to maximize their opportunity to achieve native-level skills.

• Essentailly, the neural circuitry supporting language learning operates differently and better during the early years.

A Human Environment

• Children must be exposed to other people using signed and spoken language.

• Newborns prefer listening to speech rather than artificial sounds, showing that infant’s auditory preferences are fine-tuned through experience with human language.

  Infant-directed speech (IDS)

• Infant-directed speech is the distinctive mode of speech used when speaking to infants and toddlers.

  • Adults tend to speak with greater pitch variability, slower speech, shorter utterances, more word repetition and more question.

  • They also enhance the clarity of vowels, adjust the sound of their voice, and exaggerate their facial expressions.

• Infants prefer this to adult-directed speech (ADS), even when it’s in another language.

• IDS is not universal, but it is common due to different cultures.

The Process of Language Acquisition

Speech Perception

• Speech perception begins in the womb.

• The basis for this is prosody which is the characteristic rhythm and intonational patterns with which a language is spoken.

Categorical Perception of Speech Sounds

• Categorical perception is the perception of speech sounds as belonging to categories.

  • ex. the phenome /b/ is related to /p/ and they are produced the same way, except for one difference - the length of time between when air passes through the lips and when the vocal cords start vibrating, which is referred to as voice onset time (VOT).

  • the VOT for /b/ is less than 25 ms and the VOT for /p/ is greater than 25 ms, and so adults automatically divide the sounds /ba/ and /pa/ into /b/ and /p/.

• Perceiving a continous signal as two categories (in this situation a continuous signal of /ba/ and /pa/) is useful because it focuses listeners on differences that are linguistically meaningful (difference between /b/ and /p/) instead of meaningless differences (like the difference between a 10ms VOT /b/ versus a 20ms VOT /b/).

  • In this situation, you need to differentiate these phenomes because “bat” is a different word than “pat”, but the VOT of the word “bat” said in different occasions is of no consequence linguistically.

• Young infants draw the same sharp distinctions between speech sounds as adults.

  • This was learned through an experiment using habituation and dishabituation (when the infant showed signs of being used to one sound, another was played and the infant was interested again, showing they can tell the difference).

• Young infants actually make more distinctions than adults do. They can distinguish between phenemic contrasts made in all languages of the world, which is about 600 consonants and 200 vowels.

  • In English, the sounds /r/ and /l/ make a difference in language, but not in Japanese. As infants have not learned a language yet, they hear the difference, but Japanese-speaking adults would not.

  • Arabic-speaking adults perceive a difference between the /k/ sounds in “keep” and “cool” but English-speaking adults do not because it is essentially the same sound in the English language.

  • This shows that adults do not percieve differences in speech sounds that are not important in their native language, which makes it harder for them to become fluent in a second language.

Developmental Changes in Speech Perception

• By 12 months, infants become less sensitive to differences between nonnative speech sounds, like adults are.

• Perceptual narrowing is not an entirely passive process, and infants were more successful at learning languages from the screen with a peer, than alone.

Word Segmentation

• Word segmentation is the process of discovering where words begin and end in fluent speech.

• Infants pick up regularities in their native language to help them find word boundaries.

  • One example of a regularity is stress-patterning where infants expect stressed syllables to begin words and use this information to pull words out of fluent speech.

  • Another is the distributional properties of the speech they hear, which are the certain sounds that are more likely to occur together than others.

• The most noticeable regularity is their own name, and at as young as 4.5 months, they recognize their name as theirs, and can pick it out of background conversations, which helps them learn other words their name is linked to.

Preparation for Production

• Infants make many noises, with helps them gain motor control over their vocalizations, and as it is expanding, they realize their vocalizations elicit responses from others, which leads them to engage in dialogues of reciprocal cooing with their caregivers. Infants with more responsive caregivers are more likely to use more mature vocalization patterns.

Babbling

• Babies begin babbling, which is saying repetitive consonant-vowel sequences like “bababa…” or hand movements (for learners of sign languages) between 6-10 months of age.

• Infants’ babbling gradually takes on the sounds, rhythm, and intonational patterns of the language infants hear/see daily.

Early Interactions

• In a conversation, mature participants alternate between speaking and listening, and learning to take turns is faciliated by parent-infant games, like peekaboo and by giving and taking objects from a child.

• This way, the infant has the opportunity to alternate between an active and passive role, giving infants practice in bidirectional communication.

• Successful commmunication also requires intersubjectivity, in which two partners share a mutual understanding which requires joint attention, where the caregiver follows the baby’s lead and comments on whatever it’s looking at, which helps the baby understand the communicative nature of pointing by 12 months of age.

First Words

Early Word Recognition

• Infants begin to understand highly frequent words (like mommy & daddy) early on, and look towards whatever the words are referencing.

  • Autistic kids do this as well, proving that infants know more words than they can speak.

• With linguistic experience, infants become skilled at rapid word comprehension.

  • In a study where infants were presented a pair of objects and hear one of them being labeled, the older infant looked at the object after one syllable being uttered, while the younger one waited for the whole word to be said.

• Older children use context to recognize words

  • Ex. toddlers who are learning a language with a grammatical gender system use the gender of the article that comes before the noun to learn to recognize the noun faster.

Early Word Production

• Infants produce their first words between 10-15 months of age, but they are mispronounced thorugh leaving out difficult bits of words, (banana → nana) substituting easier sounds for harder ones (bubba instead of brother), or reordering parts of words to put an easier sound at the beginning (cagoshin instead of chicago).

• Early words refer to family members, pets and important objects, as well as frequent routines through labels (“up”, “bye-bye” and “night-night”)

• Modifiers like “mine”, “hot” and “all gone” are also used.

• Infants express their thoughts with one-word utterances, but they don’t have enough vocabulary to talk about what they want to talk about, so they use a word in a broader context than is appropriate which is called overextension.

  • Ex. children using the word dog for any 4-legged animal, and hot for any reflective metal.

• Young children also exhibit underextension which is using the word in a more limited context than appropriate.

  • Ex. using the word dog in reference to only their dog, but not the neighbours.

Word Learning

Adult Influences on Word Learning

• Caregivers influence word learning by talking to their children.

• The amount and quality of talking that children hear predicts how many words they learn.

  • Stressing or repeating new words helps along with naming games.

• Toddlers show better word learning when the object being labeled is centered in their visual field.

Children’s Contributions to Word Learning

• Children expect that a given entitity has only one name (mutual exclusivity).

  • Bilingual and trilingual infants who are used to hearing more than one name for a given object are less likely to follow the mutual exclusivity assumption.

• The whole-object assumpion is when children expect a novel word to refer to a whole object rather than to a part, property, action or other aspect of the object.

  • Ex. if a child is shown an object and given the label truck, the child will assume truck refers to the entire object, not specific parts of it.

• Children use a variety of pragmatic cues to word meaning by paying attention to social contexts.

• Infants can use an adult’s emotional response to infer the name of a novel object they can’t see.

  • If the adult is searching for their keys, and they are disappointed when they pick something that isn’t it up, but are happy when they find it, the infant will assume the object they picked up when they are happy are the keys.

• If an adult’s labeling of an object conflicts with a child’s knowledge of it, they will accept the adult’s label if they used it intentionally.

• Young children also use the linguistic context in which a word occurs to infer its meaning (whether it’s a verb, count noun, or mass noun).

• Object shape is useful in word learning because shape is a good cue to category membership.

  • Attention to shape is evident in toddler’s recognition of familiar words.

    • Ex. when shown known objects with wrong colours (pink cow & a black-and-white patched pig), toddlers still look at the cow when they hear cow, but are just a little slower to do so.

• Another useful cue to word meaning is repeated correspondence between words the child hears, and objects the child observes in the world (cross-situational word learning).

• Children figure out meanings of new words by using the grammatical structure of the sentences in which those words occur (syntactic bootstrapping).

  • Ex. 2-year-olds are shown a video of a duck using its left hand to push a rabbit down, while both animals waved their right arms in circles. Some children heard “the duck is kraddling the rabbit” and others heard “the rabbit and duck are kraddling”. When instructed to “find kraddling”, the groups referred to what was said in the video, to figure out whether kraddling was what the duck did to the rabbit, or what the rabbit and the duck were both doing.

Putting Words Together

First Sentences

• Young children understand word combinations much earlier than when they can produce them.

• Children’s two-word utterances (“read me”, “mommy tea”, “ride daddy”, “hurt knee”, “all wet”, “key door”, and “andrew sleep”) have been described as telegraphic speech, because like telegrams, nonessential elements are left out.

• Many children continue to say short utterance wheras others move on to sentences of 3 or more words.

Grammar: A Tool for Building New Words and Sentences

• Human languages are generative (through the use of the finite set of words and morphemes, individuals can create an infinite number of sentences and express an infinite number of ideas).

  • In English, nouns are made plural by adding s, and verbs are put into the past tense by adding ed…

  • Young children recognize these patterns and can generalize them to novel words.

    • Ex. young children were shown a made up animal called a “wug” and were asked what two of the animals would be called, to which they replied “wugs”, because they are generalizing beyond words they had heard before.

• Children initially use the correct irregular forms of irregular words, but they start making occasional overregularization errors which are are speech errors in which children treat irregular forms of words as if they are regular.

  • Ex. child who previously said “men” and “went” may start saying “mans” and “goed”.

• Parents play a role in grammatical devleopment through filling in missing parts of children’s incomplete utterances, but not usually by correcting grammatical errors, as parents generally ignore them.

• Infants can learn new grammatical patterns through generalizing beyond the specific items they have heard.

  • Ex. infants who have heard a list of 3-word sequences in which the second word is repeated like: “le di di, wi je je, de li li”, recognize this pattern when it is presented in new syllables like “ko ga ga”.

Conversational Skills

• Young children’s speech is often directed to themselves rather than to another person, and when conversing with other children, their conversations tend to be egocentric.

  • Piaget labeled young children’s talk with peers as collective monologue with their conversations not linking to each other at all.

    • Ex. Jenny: My bunny slippers are brown and red and sort of yellow and white.

    • Chris: I have a piece of sugar in a red piece of paper.

    • Jenny: We bought them. My mommy did. We couldn’t find the old ones.

    • Chris: Can’t eat the piece of sugar, not unless you take the paper off.

• As they get older, children become better at sticking to the same topic as the person they are talking to, and can talk about the past.

• 5-year-olds produce narratives (descriptions of past events with the form of a story)

• Parents assist their children in producing coherent accounts of past events by scaffolding through filling in details and such.

• Pragmatic development is needed to become a good conversational partner as it allows listeners to go beyond the words and grasp the actual meaning in terms of rhetorical questioning, sarcasm, irony and such.

• Children also learn to use info other than words to read between the lines in a conversation (ex. when told to “look at the doll” 4-year-olds look at the intact doll when told to with positive effect, and at the broken doll when told to with negative effect).

• Several recent studies suggest that children’s own experiences influence their ability to take other people’s perspectives in communication settings.

  • Ex. living in a diverse linguistic environment attunes children to the challenges of communication and the need to take other’s perspective in order to communicate effectively in a way monolingual environments do not.

Later Development

• School-age children become increasingly capable of reflecting upon and analyzing language & master more complex grammatical structures like the use of passive constructions in English.

• One consequence of this, is the increasing appreciation for multiple meanings of words which leads to puns, riddles, and jokes.

Theoretical Issues in Language Development

Chomsky and the Nativist View

• B. F. Skinner proposed a behaviourist theory of language development.

  • They believed development is a function of learning through reinforcement and punishment of overt behaviour.

• Noam Chomsky countered this by pointing out some of the reasons why language cannot be learned via reinforcement and punishment.

1. Generativity (as discussed earlier)

2. Chomsky proposed that humans are born with a Universal Grammar (a hard-wired set of principles and rules that govern grammar in all languages).

Ongoing Debates in Language Development

• Current theories all acknowledge Chomsky’s observations such as that human languages share many characteristics.

• Theories have to explain how language users can generalize beyond the specific words and sentences they have been exposed to (“wug” example).

• There are two key dimensions in understanding language development:

  1. The contributions of nature vs nurture

  2. Did the cognitive and neural mechanisms underlying language learning evolve solely to support language learning (domain specific) or are they used for leanring many different kinds of things (domain general)?

• First dimension: theories have countered Chomsky’s argument about the universality of language structure by pointing out that there are univerals in children’s environments as parents need to comunicate about certain things with their children, and these are likely to be reflected in the language children learn.

  • Accounts focused on social interaction say that everything about language development is influenced by its communicative function.

• Second dimension: according to Chomsky’s views, the cognitive abilities that support language development are highly specific to language.

• An alternative view suggests that the learning mechanisms underlying language development are acutally quite general and not restricted to language learning.

• Computational modeling has played an important role in the development of modern theoretical perspectives as it helps researches manipulate the innate structure and environmental input to figure out what is crucial in simulating children’s language acquisition.

  • Connectionism is a type of computational model that emphasizes the simultaneous activity of numerous interconnected processing units.

    • The model learns from experience, gradually strengthening certain connections among units in ways that mimic children’s developmental progress, and this has proven to be successful in modeling specific aspects of language development, like children’s acquisition of the past tense and shape bias for word learning.

Nonlinguistic Symbols and Development

Using Symbols as Information

• The primary function of many symbols is to provide useful information (ex. map for locating a particular place).

• Using a symbolic artifact like a map requires dual representation, meaning the artifact needs to be treated as a real object, and as a symbol for something other than itself.

• Young children have dificulty with dual representation, which is similar to Piaget’s preoperational stage where children have difficulty considering multiple dimensions of objects at the same time in conservation tasks.

  • Because of this, they cannot use symbolic artifacts like a mini-scale model of a regular size room to compare and find differences.

• Young children have particular difficulty with symbols intended to represent themselves, even when they are the same size as the child.

• Increasing ability to achieve dual representation lets children discover the abstract nature of symbolic artifacts.

• Younger children from cultures where pictures are everywhere are more likely to understand that pictures can serve a symbolic function than those in cultures where they are rarely exposed to pictures.

• Advances in picture perception provide evidence for early forms of symbolic understanding.

• Increased understanding of this helps children avoid action errors as well as symbols of chairs and cars that help children with the motor behaviours needed.

Drawing and Writing

• When young children start making marks on paper, they do exactly that with no attempt to produce recognizable images.

• At about 3-4 years of age, children start to draw pictures of something, and exposure to representational symbols affect the age at which they begin to draw them.

• Children from homes filled with pictures produce such images earlier than children from homes with few pictures.

• Children want to draw before their motor and planning capabilities allow them to.

• Children’s scribbles reflect their emerging understanding of writing as well, as they produce different types of scribbles for writing vs drawing.

  • Children initially depend on perceptual similarity between the symbol and what it is intended to represent (longer words may be “written” with longer scribbles).