L20: Language Flashcards
What is Language?
Language encompasses a lot of the systems that we have learned so far.
Combines different parts of the brain’s systems
Takes lower sensory and motor system to interpret and produce language
Visual stimuli of written language
Fine range motor control for typing/writing
Need good coordination of vocal muscles to express language
Cognitive - learn how to make sounds and map things in our mind
Language is universal
Language has evolved in multiple places at multiple times
Fairly closely in time around the world
7102 living languages in the world
What types of things are universal to all languages? Basic set of rules?
Critical period of learning language: 5-6 years old
If you don’t learn language past this point, it will be hard to learn a language fluently
Language is uniquely human
Other animals have different communication systems:
Sonar, echolocation, barking
Syntax order matters for expression in English
All languages have some way of having hierarchical relationships
Helps us communicate nuanced thoughts
Animals are usually not able to communicate with complicated syntax but can pick up on words
Speech Production
100+ muscles:
Allows us to pronounce certain words
Takes a lot of practice to form certain sounds that are unfamiliar to us
Native language is taken care of subconsciously
Motor cortex control
Language in the Brain
1770s: Patient can exhibit aphasia while other cognitive abilities remain intact
Specialized brain areas for language?
Late 1800s: Broca and Wernicke
Aphasias
Broca’s - syntax; understanding is good, but finding words is difficult
Wernicke’s - produces sentences that have syntax structure but the topic is wrong
Conduction Aphasia
Arcuate Fasciculus - bundle of axons that connects wernicke’s and broca’s areas of the brain
Conduction aphasia- Broca’s and Wernicke’s work fine but are not connected to each other
Paraphasic - say a word you don’t mean to say; saying week instead of month
Phonological - substituting words that sound very similar; hen for pen
Wernicke-Geschwind Model
Oversimplification of what is happening (refer to model in slides)
Wernicke predicted conduction aphasia
Asymmetrical anatomy
Planum temporale: heart of Wernicke’s area, larger on the left in 65% of people
Left hemisphere seems to be more specialized than right for language
Left lateral fissure tends to be longer than the right
However, most people are right-handed too — is LH really specialized for language or just fine motor control
Left Hemisphere Language Dominance
“Wada” procedure –
Inject barbiturate that temporarily affects activity into one hemisphere
Surgeons have been doing this to see if people have language localization in the left hemisphere
Left handed - right hemisphere dominant for language
In the majority of people
Impaired right hemisphere - normal language abilities
Impaired left hemisphere - aphasia
Evidence from neuroimaging
Left-dominant subjects
(as determined by Wada
procedure)
* fMRI showed left
lateralization but
significant activations in
both hemispheres during
language tasks
evidence from split brains
Few cognitive deficits, except in tasks which require info to cross hemispheres
Cutting through corpus callosum for severe epilepsy
Left language pathways cannot “see” or name objects in the ipsilateral hemifield
Able to name objects by touch only in the right hand
Language across modalities
“Language” is not just speech
In fluent multilinguals, aphasia-causing lesions usually to tend affect all languages
Overlapping brain areas are used for sign and speech
However, age of acquisition may affect left-lateralization of sign language processing
Evidence from brain stimulation
Electrical stimulation during awake brain surgery can disrupt:
Speech production
Grammar
Object naming
Reading
Facial movement
Sapir-Whorf Hypothesis
Does the language we speak influence our thoughts/memories
he hypothesis suggests that people who speak different languages have different ways of thinking because of the semantic categories of their native language.
