Approaches to study of language development
- Language socialization: A description of children’s language use in social contexts and an account of the social processes by which children come to use language in the manner of their culture
- Linguistic: the Language Acquisition Device (LAD) must contain some knowledge of the structure of language in order for language acquisition to be possible — this innate knowledge cannot be specific to any particular language thus it is a Universal Grammar (UG)
- Learnability approach: focuses on explaining the fact that language is acquired (i.e., that language is learnable).
- Developmental approach: focuses on explaining the course of language development.
Nature vs Nurture
- Is the development of language in children the result of human innate knowledge (e.g. walking upright) or is it the result of the experiences of children and how they are raised (e.g. learning calculus)?
- Empiricism: the mind at birth is like a blank slate; all knowledge and reason come from experience
- Nativism: knowledge cannot come from experience alone. The mind must have some preexisting structure in order to organize and interpret experience
- Interactionism/constructivist: acknowledges there must be some innate characteristics of the mind that allow it to develop language based on experience but places greater emphasis on accounting for children’s language-learning experiences
Cognitivism vs Behaviourism
- Behaviourism: change in behaviour occurs in response to the consequences of prior behaviour; behaviour can be fully accounted for in terms of things external to the mind
- Cognitivism: we cannot understand behaviour without understanding what is going on inside the mind of the organism producing the behaviour
- Critical period hypothesis: language must be learned within a biologically determined window (comparable to birds and imprinting)
- Sometimes also called the sensitive period or optimal period (less sensitive than critical period)
Measuring sound discrimination
- Prosody: includes learning about the intonation, stress, pitch of a language.
- Categorical perception: when a range of stimuli that differ continuously are perceived as belonging to only a few categories
- Phoneme Boundary Effect: example of categorical perception. e.g. the phonemes /b/ and /p/ differ along a single acoustic continuum (voice onset time), but listeners hear each stimulus as either a /b/ or a /p/, nothing in between
- Distributional learning: learning from simply being exposed to frequency distributions of speech sounds in one’s surroundings
- Statistical learning: learning by counting the frequency with which one stimulus is followed by another
- Rule learning: a stronger claim than statistical learning, claims that babies can learn a pattern that must be described in terms of symbols (or variables) that stand for any sound. Babies learn algebraic rules, not just statistical regularities
- Phonological bootstrapping hypothesis: children use phonological cues (e.g. nouns tend to have first-syllable stress whereas verbs have second-syllable stress) to break into grammatical structure
- Prosodic bootstrapping hypothesis: pauses and changes in intonation at phrase boundaries
5 stages in early speech production
- Reflexive Crying and Vegetative Sounds
- Burps, sneezes, anything that accompanies biological functions
- Cooing and Laughter (elicited by social interaction)
- Vocal Play or Expansion Stage
- In first few months, the only recognizable speech sounds are vowel-like. The first recognizable consonant-like sounds are heard at around 2 to 3 months of age, and tend to be back of the mouth (velars), such as [g] and [k].
- Reduplicated Babbling (e.g. bababa)
- Deaf child also babble but at a later time than other children. The number of sounds produced gets smaller (not larger) over time.
- Non-Reduplicated/Variegated Babbling (e.g. bagiga)
- Wordless sentences are often referred to as jargon
- Impacts of experience in speech production
- Input from adults – affects sounds and prosody in babbling. This is also influenced by the language that they hear (babbling drift)
- Vocal feedback from own productions
- Social feedback
Phoneme Acquisition Time
- Why are some phonemes acquired later than others?
- Ease of articulation
- Frequency in the input
- Functional load – how many words in the language use this sound?
- Early: /p/, /b/, /d/, /m/, /n/, /j/, /w/, /h/
- Middle: /t/, /k/, /g/, /f/, /v/, /tʃ/, /ŋ/, /dʒ/
- Late: /θ/, /ð/, /s/, /z/, /ʃ/, /ʒ/, /l/, /r/
Experimental approaches for studying infant’s perception
- Cross-language speech perception: see Werker & Tees
- High-amplitude Sucking Technique
- Babies like to hear sounds
- Babies lose interest in a sound when it is presented repeatedly (habituation)
- Babies who have lost interest in a previously repeated sound will become interested if a new sound is presented (dishabituation)
- Works best for <0;4
- Conditioned Head Turn Procedure
- Babies are interested in moving toys
- Using the presentation of the moving toy as a reward, babies can be trained to turn their heads when they hear a change in a sound being presented
- Works best for 0;5-1;0
- Intermodal Preferential Looking Paradigm
- Placing a child on their mother’s lap in front of two video monitors, which play two different events simultaneously.
- A speaker between the two monitors plays a verbal sentence that matches only one of the videos.
- A hidden observer measures how much the child looks at each screen.
- If the child watches the correct monitor longer and more quickly than the incorrect monitor, they are deemed to have understood the sentence.