The Biological Basis of Language (Acquisition) LIGN 171 Wednesday, January 17, 2001 Andy Hickl
Where we’re headed…
Why humans (think we) are so special…
Why we can’t talk to (or with) the animals…
The neurocognitive basis of language, or “BRAINS, master, MORE BRAINS”!
Summary of Section 2
What do you believe?
There’s still something about Human Language
All humans seem to acquire language following the roughly the same developmental path .
At birth, infants seem to have an infinite capacity to learn any language .
Humans can create new languages to communicate with other humans.
Language learning seems to be subject to specific critical period effects .
Pidgins and Creoles
Pidgin : a structurally-simple language that arises when people who share no common language come into contact.
Vocabulary is old, but (limited) grammar is new.
Often limited to specific situations, communicative functions, etc.
Hawaiian Fish Market Pidgin
Pidgins and Creoles
Creole: a language that develops when children acquire a pidgin as their native language. (e.g. Swahili, Tok Pisin, Nicaraguan Sign Language…)
Big boost in grammatical complexity as time goes by, more speakers acquire it…
Grammatical properties of the creole don’t have to look like either of the “parent” languages.
All creoles share some universal grammatical properties, regardless of how/when/where they were created.
Where does this come from?
Something in the human mind/brain/genetic makeup?
Something about the way the new (creole) languages are used communicatively?
Something particular about the languages that have often been involved in forming creoles?
Nicaraguan Sign Language
1978: First deaf schools in Nicaragua.
More complexity found with who learned the language at an early age.
Idiosyncratic Signing Systems Pidgin NSL Fully-formed NSL
How does this happen? (Two familiar views, no?)
All humans have an innate “linguistic bioprogram” or a “core grammar” which allows them to learn or (in some cases) create languages based on the input they receive.
Creoles get to be more complex grammatically because they are used in a wider variety of communicative situations – these new uses require the language to encode more differences.
Critical Period Effects
Critical Period: the biologically-determined period in which acquisition of a behavior or property must occur to be successful.
Some environmental input is necessary for development to occur “normally”:
Imprinting in ducks, geese
Photoreceptors in humans
Kids gone WILD! (The cases of feral children…)
Limited number of children have been found who have developed without exposure to language .
Victor of Aveyron (19 th century France, ???)
Isabelle (1930’s France, 6 years old)
Normal (?) use of language as an adult
Genie (1970’s California, 13 years old)
Abusive situation, likely brain damage
Learned vocabulary, limited (if any) syntax.
Language processed on the right hemisphere , not the left.
No pressure, dudes… (More evidence for the Critical Period Hypothesis)
Second Language Acquisition :
Younger learners native fluency.
Older learners (>17) never quite make it.
ASL Acquisition :
Children of Deaf Adults (CODAs) have an advantage over later-learners of ASL
Less chance of recovery of linguistic function after age 5.
How does this happen?
Language modules are only fully-operational during a specific period of time . After that, a child’s conception of grammar (and language) is relatively fixed.
The CP for learning language is the time when the child’s cognitive capacity is best attuned to learning the complex systems of grammar.
The tough questions… (Reprised from before…)
Why does language acquisition always follow the same developmental path ?
How can infants learn any natural language ?
How do humans create new languages in order to communicate?
Why should language learning be subject to specific critical period effects ?
Why can’t it be both ?
Short answer : It probably is.
Longer answer :
The development of language isn’t directly observable – so we can’t reliably determine what is innate and what is ultimately learned.
Approaches like nativism and empiricism give us logical extremes to start with…
But we can do better, can’t we?
Consider this… (New insights that might prove useful…)
Human infants pay attention to faces and people who are talking.
Human infants like listening to human speech – and especially speech from their own language.
Human infants constantly seek new sources of stimulation.
Human infants attach to nurturing figures and environments.
Human infants babble long before they are able to produce words.
What’s my motivation?
Any time we ask why a behavior evolved in the way that it did, we have to consider 4 different factors:
How did the behavior develop?
How does the behavior develop in infants?
How does the body perform such a behavior?
Why does the individual engage in the behavior?
The Teleological Trap (For catching Teleogies, right?)
Insects developed wings in order to fly.
Birds fly south in winter because it’s too cold for them in the north.
Kids babble at 9 months because they’re getting ready to start speaking.
The notion that a process (like development) proceeds to achieve a single logical goal.
What’s wrong here?
We can’t say that kids start babbling in order to get to language any more than we can say that insects decided that wings would be a good idea!
Kids (like insects) have no idea where the course of development will take them!
So, what can we say?
Instead of adopting a teleological approach , let’s try a teleonomic one.
The notion that a process (like development) proceeds in a sequence of stages, each of which facilitates or reinforces the next step in the sequence.
Okay, this is more than a little fuzzy…
A Teleonomic Explanation Behavior Kid learns mother’s voice. Kid recognizes mother. Kid figures mother is a good person to attach to. Kid is taken care of by mother. KID LIVES! Kid isn’t so scared of the world. Kid is comfortable in a nurturing environment Kid undergoes fruitful social-cognitive development. Kid exposed to plenty of language stimuli from mother. KID ACQUIRES LANGUAGE!
We can build similar chains of events for most behaviors…
A teleonomic approach should make some intuitive sense…
Complex behaviors like language can now be seen as a series of complementary developmental advances.
Unfortunately, this doesn’t get rid of the nativist/empiricist distinction entirely: we still need to figure out where each individual advance, skill, or module “comes from”…
Hopeful Monsters… Behavior Kid learns mother’s voice. Kid recognizes mother. Kid figures mother is a good person to attach to. Kid is taken care of by mother. KID LIVES! Kid isn’t so scared of the world. Kid is comfortable in a nurturing environment Kid undergoes fruitful social-cognitive development. Kid exposed to plenty of language stimuli from mother. KID ACQUIRES LANGUAGE!
Mutation causes a leap “across” the teleonomic chain.
…and Missing Links. Behavior Kid learns mother’s voice. Kid recognizes mother. Kid figures mother is a good person to attach to. Kid is taken care of by mother. KID LIVES! Kid isn’t so scared of the world. Kid is comfortable in a nurturing environment Kid undergoes fruitful social-cognitive development. Kid exposed to plenty of language stimuli from mother. KID ACQUIRES LANGUAGE!
Without the acquisition of certain stages no language.
Hopeful Monsters: A big assumption
The hypothesis that a mutation could be the single factor that allows humans (and only humans) to have language is a powerful one…
It presumes that human language may be fundamentally different than any other form of animal communication.
The flip side: Missing Links
Conversely, the hypothesis that animals lack certain cognitive aspects needed to process language forces us into an opposite position:
Human language may not be fundamentally different than the forms of communication employed by animals .