Language development and developmental language disorders Flashcards
Describe the timeline of language development.
We learn language relatively easily in a distinct timeline:
3 months: Gurgling
6 months: Babbling. Here already we can start to detect structure.
12 months: first words
2 year: 150-300 words and a few short sentences
3 years: ~1000 words and asking short questions
5 years: identify letters, longer sentences
Explain critical periods for language development.
- children who are not exposed to language (deprived) never acquire more than rudimentary language, despite of therapy
- babies can distinguish all phonemes, but by 18 months, we lose the ability to distinguish those we have not heard
- Whether deaf people are exposed to any language early in life determines their later abilities to learn languages
- The age at which we acquire a second language determines our final efficiency at that
language. If we learn it before age 7 we are fluent
Describe the following theories of Language development: Behaviorist
- Language development occurs through the principles of learning including association and reinforcement and habit forming
- children modify their language through imitation and reinforcement from parents
- criticism: learn words too fast for them to be learned through reinforcement
Describe the following theories of Language development: Nativist
- language as basic instinct hardwired into our brains
- language develops in children exposed to it, no teaching or training of reinforcement required
Criticism:
- the underlying feature of the language acquisition device are not entirely universal
- languages without nouns or verb phrases, or tenses
Describe the following theories of Language development: Connectionist
- concerned with word associations
- linkages depend on the relative strength of synaptic connections in the relevant parts of the brain
Discuss if language development is unique to humans.
Many have tried to teach chimps language (either spoken or ASL)
Some conflicting results:
- spoken language cannot be learned be chimps
- ASL somewhat learned, but only basic sentences (one chimp learned > 1000 signs, but makes signs in rapid sequences with no meaning)
- using a lexigram board, a chimp at 8 y/o is comparable to a 2 y/o, and unlikely to improve
Describe the genetics of language.
We know little about this:
- the gene FOXP2 has been declared “the language gene” as deficts in this gene leads to deficits in speech production, however it seems to be extremely conserved between species, and seems to be related to plasticity in the motor related brain circuits - it might just be related to motor planning/sequencing, and thereby deficits in this gene might lead to secondary consequences of speech production, and not be “the language gene” per se
Describe how to categorize developmental language disorders (DLD).
Umbrella term to describe children whom experience language difficulities that create barriers to communication or learning, and whose problems are unlikely to be resolved by 5, and whose problems are not associated with known biomedical conditions (brain injury…)
Extremely common (at least 7 % of the population)
Describe the characteristics of DLD: semantics and phonology.
- difficulty retrieving words
- can also have trobles learning new words
- may leave out phonomes (“phant” instead of “elephant”) or substitute consonants
Describe the impact of DLD.
- 4 x more likely to have maths difficulities
- 2x more likely to be unemployed in adulthood
- lower education attainment
- 2x more likely to develop emotional problems, and behavioral difficulities
- difficulities in establishing peer relationships
Describe what we know about the genetics of DLD.
- not straightforward - clearly there is a genetic link (monozygotic twins have a high degree of concordance), and high risk for DLD if 1st-degree relative has DLD.
- many different genes has been associated
- current belief: common risk variants each confer a genetic susceptibility that contributes incrementally to the overall risk
Describe what we know about the neurobiology of DLD.
We know suprisingly little:
- brain imaging studies have suggested changes in dorsal
and ventral pathways linking the important cortical language areas in the brain.
- recent study: changes in cortical-subcortical connectivity with a reduction in signals related to myelin in the dorsal striatum
Describe what we know about environmental modulators DLD.
Genetics are important but environment also seem to play an important role
Different environmental factors:
- premature birth/low birth - - weight
- birth complications
- poor nutrition
- maternal smoking (during pregnancy)
- being a younger sibling
- lower maternal education
Give 2 intervention strategies for DLD.
- Word maps
- The shape coding system
Describe the “Word Map” strategy.
- used for building vocabulary by associating the word with other words that either sound alike, have the same meaning, mean the opposite, start with the same letter etc.
- this will create a “word map” for each word to help to access this word, its
sound characteristics and it’s meaning again
