L5 Language Development

Development Psychology

DeCasper & Fifer, 1980

sucking behaviour indicates newborns recognise their mother’s voice compared with a stranger’s 

DeCasper & Spence, 1986

infants recognise a passage heard in utero compared to a new passage

Kisilevsky et al, 2003

measures of fetal heart rate at full term show increase to mother read vs stranger read poem

→ Evidence for very early sensitivity to speech and capacity for learning

May be based on speaker identity/intonation rather than speech processing/comprehension

Perception of Phonemes

At/soon after birth…

• Infants discriminate similar-sounding phonemes (b vs p)

• At 1-4 months, there is evidence for categorical perception – better on either side of a boundary used by adults (Eimas et al, 1971)

• More attention to differences in phoneme than differences in voice of speaker (Kuhl, 1979)

Perceptual narrowing occurs later in the first year of life…

Werker & Tees, 1984 – Ability to discriminate phonemes in another language fades between 8-10 months 

→ Early capabilities + learning indicate “experience-expectant” system – one with an organisation that supports the learning of phonetic categories in any language 

Speech Segmentation 

Difficult task – sounds run into each other, sometimes words do not have pauses between them 

Infants pick up on statistical patterns in language as a cue to segmentation

Transitional probabilities

in continuous speech, some sound combinations are more frequent than others 

Frequent combination → likely to be within a word

Infrequent combination → likely to be between words 

Saffran et al, 1996

 infants rapidly learn such probabilities even in artificial languages

Werker & Gervain, 2013

number of other cues correlated with word boundaries (stress patterns) also learnt and employed at 7-9 months 

These mechanisms for statistical learning indicate infants come equipped to learn meaningful patterns and distinctions in the language they are exposed to 

Later, recognition of some individual words → help determine where other words exist in stream

Speech Production - Kuhl, 2004

Infants produce non-speech sounds (1-3 months)

Infants produce vowel-like sounds (3 months)

“Canonical babbling” (7 months)

Language-specific speech production (10 months)

First words produced (12 months)

Semantics

Dramatic vocabulary development from 18 months → 6 years

Comprehension of 50-100 words at 18 months

→ 900 words at 2 years

→ 8000 words at 6 years

Smith, 2000

Associative/Perceptual Account

Associative learning plus perceptual similarity ← picking up on statistics in the environment

Tomasello, 1988; Bloom, 2001

Social Account

Children need social cues such as pointing and eye gaze to learn words 

Hollich et al, 2000 – Emergentist Coalition Model (ECM)

A hybrid approach

• Children learn words using perceptual, social, and linguistic cues

• Their reliance on cues changes over time

Mostly associative in 1st year of life (Pruden et al, 2006)

Increasingly reliant on social and linguistic information (Golinkoff & Hirsh-Pasek, 2006) 

• Incorporates and builds on previously documented constraints and biases 

Assumption of mutual exclusivity

children expect that different words mean different things (Markman & Wachtel, 1988) 

• 3-4 year olds assign newly introduced nonsense syllable to a novel object they don’t yet have a word for rather than a familiar one with an associated meaning 

• New labels provided for known objects are often attributed to a part of the object or substance it is made out of rather than an alternative name for the object 

Gleitman, 1990 – Syntactic Bootstrapping

Using grammar to infer word meaning

Children use a grammatical distinction to help assign meanings to the words they hear (“gorping” as opposed to “gorping with”)

Roy et al, 2009

 longitudinal study of a single child and his linguistic environment

Acquisition of individual words correlates with how caregivers “tune” their speech to make learning a new word easier 

Syntax development

Without grammar → telegraphic speech, very basic communication 

Earliest word combinations (~18 months)

With grammar → express more complex relations

Brown & Hanlon, 1970

 parents often correct factual mistakes, but not grammatical errors → syntax is NOT learnt through explicit corrections from parents

Skinner’s Operant Conditioning Model, 1957 

Language can be learned through imitation, trial and error, and reinforcement

A child acquires verbal behaviour when people react in certain ways to certain combinations of sounds/words they make

Chomsky’s Innate Language Acquisition Device, 1959-1965

behaviourism studies argued that internal representations are needed to produce language 

Speakers hear and use the surface structure but are comprehending the deep structure 

Rules relating to deep structure → too complex to be learned by association

→ Innate capacity for grammar – some kind of expectations/constraints for what kinds of grammars are possible in human language 

Grammatical rules are more efficient and can be applied to new words – expectations have to be remembered individually 

Slobin, 1985

 children’s grammatical rule learning

• First remember specific examples

• Learn to apply general rule

• Over-regularise the rule

• Individually correct over-regularised assumptions through trial and error 

Fiser & Aslin, 2002

evidence for the overlap of language learning mechanisms and other learning mechanisms

infants also learn co-occurrence statistics of visual stimuli – broader learning rules may underline some aspects of language acquisition

Rumelhart & McClelland, 1985

a general-purpose model of statistical learning could explain errors that seem specific to language (ie, over-regularisation of the past tense)

Dehaene-Lambertz et al, 2002

speech processing specifically localizes in the temporal lobe at 3 months

However,

• Different cortical regions can support next to normal language acquisition in cases of early brain damage 

• Congenitally deaf patients show different functions in areas normally supporting oral language

Miller et al, 1975

some auditory mechanisms involved in early speech perception are shared with other species (ie, chinchillas)

Brainard & Doupe, 2002

 like language, birdsong is learnt through experience, and like infants, birds have sensitive periods

Fisher & Scharff, 2009

 human language includes ancestral mechanisms shared with other species, and the nature of the overlap is still unclear 

Neuronal recycling hypothesis – Dehaene et al, 2010; Dehaene & Cohen, 2011 

Reading acquisition partially recycles a cortical territory evolved for object and face recognition 

Literate vs illiterate participants – when learning to read, representation of written words partially takes over the “visual word form area” (VFWA)