Transcript Week 2 - University of Pennsylvania

LING 001 Introduction to Linguistics
Fall 2010
Language Acquisition I:
Overview
Biological capacity to learn
Stages of language acquisition
Mar. 15
Learning language
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One of the most impressive achievements of the human child is its
ability to learn the complexities of a human language in just a few
years, without any formal instruction.
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Imagine you were a newborn infant:
• How would you separate the sounds of speech from ambient
acoustics?
• when-we-speak-we-do-not-pause-between-words
• Everyone’s speech is different: how to neutralize the differences?
• How do we learn “dog” is a noun - and also a verb?
• A sentence contains many parts - which ones “count”? (e.g.,
constituents)
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Only humans--and all humans--but no other species have language.
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Something must be in our genes.
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Biological capacity
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At birth, the infant vocal tract is in some ways more like that of an ape
than that of an adult human. In particular, the tip of the velum reaches or
overlaps with the tip of the epiglottis.
As the infant grows, she gradually stretched out the pharynx by lowering
the larynx. The result of these changes is to make it possible for the
tongue to move forward and back, up and down, in a way that creates
resonant cavities of different sizes in various places in the vocal tract.
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Biological capacity
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At about seven months, "canonical babbling" appears: infants start to
make extended sounds that are chopped up rhythmically by oral
articulations into syllable-like sequences, such as [babababa],
[nananana], [babigagu].
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No other animal does anything like babbling. It has often been
hypothesized that vocal play and babbling have the function of
"practicing" speech-like gestures, helping the infant to gain control of the
motor systems involved in speech, and to learn the acoustical
consequences of different gestures.
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Biological capacity
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Categorical perception
• A change in some variable along a continuum is perceived, not as
gradual but as instances of discrete categories
• Discrimination between stimuli is much more accurate between
categories than within them
• The ability to discriminate is only as well as one can identify
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Biological capacity
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Categorical perception has been observed in many contrasting pairs of
speech sounds.
Unique to language? No. Color perception is also categorical.
Unique to humans? Probably not. Chinchillas, quails, etc. can
distinguish the bah-pah categories as well.
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Biological capacity
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Perceptual magnet effect
• Phonetic categories have internal structure in which category
prototypes, i.e., exceptionally good instances of phonetic categories,
play an important role.
• The prototype of a category functions like a perceptual magnet for
other category members. The prototype attracts nearby members of
the category, rendering them more perceptually similar to it than
would be expected on the basis of physical distance alone.
QuickTime™ and a
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Biological capacity
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Perceptual magnet effect is unique to humans.
QuickTime™ and a
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Biological capacity
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Critical period: A child must be exposed to the input during a certain
critical period, which roughly extends from birth until (the end of)
puberty. Beyond puberty, then, it would no longer be possible to acquire
a grammar in a normal way.
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“Genie”, who was isolated from society until the age of 13 1/2, never
learned to produce more than telegraphic speech.
Los Angeles Times, November 17,
Mike paint.
1970
Neal not come sad.
Girl 13, Prisoner Since Infancy,
I like elephant eat peanut.
Deputies Charge; Parents Jailed
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“Isabelle”, on the other hand, was isolated until the age of 6 1/2, and
within a year and a half she had mastered complex grammar.
Why does the paste come out if one upsets the jar?
Do you go to Miss Mason's school at the university?
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Biological capacity
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“critical period” is easily observed in second-language acquisition. For
example, a study of Chinese and Korean immigrants to the U.S. shows
that the age of arrival to an English-speaking country is the main
determiner of how effective the new language is learned.
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Biological capacity
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The critical period resembles other aspects of maturation in humans and
animals. Failure to learn various other skills before a certain age makes
it difficult or impossible to learn that skill later:
• in ducklings: ability to identify and follow the mother
• in kittens: ability to process visual images
• in sparrows: ability to learn the father's songs
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The course of language acquisition corresponds well to the general rate
of metabolic activity in the brain, which peaks at the age of 4 and
declines through adolescence.
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It is difficult to say, however, to what extent this increased activity
permits language learning, or is induced by it.
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Stages of language acquisition
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Stage
Typical age
Characteristics
Babbling
0;6 - 0;8
repetitive CV patterns
One-word
0;9 - 1;6
Single open-class words or word
stems
Two-word
1;6 - 2;0
"mini-sentences" with simple
semantic relations
Early multiword
2;0 - 2;6
"telegraphic" sentence structures of
content words rather than functional
or grammatical morphemes
Later multiword
2;6 on
Grammatical or functional structures
emerge
Language use by the child undergoes considerable elaboration between
the age 2 and 5.
By age 5 or before, youngsters sound essentially adult.
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Phonological development
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Children from different linguistic communities exhibit significant
similarities in their babbling.
• Frequently found consonants: [p, b, m, t, d, n, k, g, s, h, w, j]
• Infrequently found consonants: [f, v, θ, ð, ʃ, ʒ, tʃ, dʒ, l, r, ŋ]
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Developmental order :
• As a group, vowels are generally acquired before consonants;
• Stops tend to be acquired before other consonants;
• In terms of place of articulation, labials are often acquired first,
followed by alveolars, velars, and alveopatals. Interdentals (such as
[θ] and [ð]) are acquired last.
• New phonemic contrasts manifest themselves first in word-initial
position. Thus, the /p/-/b/ contrast, for instance, is manifested in
pairs such as pat-bat before mop-mob.
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Phonological development
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Early phonetic processes: It's often useful to think of a child as applying
a phonological rule to the adult form, in order to produce the child's
output.
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Simplification of syllable structure: delete coda consonants.
[bi]"beat”
[so]"soap”
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Simplification of consonant clusters: Which consonant survives is a
more complex matter, but often it will be a stop consonant.
[koz] clothes
[bʌp] bump
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Deletion of unstressed syllables: Typically it's the stressed syllable that
survives. Sometimes, one unstressed syllable can also be preserved.
The result is generally a stressed plus an unstressed syllable (a
trochaic foot).
[ba] bottle
[dedo] potato
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Production vs. perception
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Children’s ability to perceive the phonemic contrasts of their language
develops well in advance of their ability to produce them.
Adult: This is your fis?
Child: No, my fis. (Rejects repeated imitations.)
Adult: Oh, that is your fish.
Child: Yes, my fis.
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Another possibility is that the child was making a very subtle distinction
that was not perceived by the adult.
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From more to less
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Experience with language alters speech perception ability, we become
attuned to the phonemes of our own languages and insensitive to
others
Japanese infants can distinguish [r] vs. [l] (but their parents can’t).
You could distinguish these sounds before…
Retroflex stop vs. dental stop in Hindi
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Vocabulary development
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By age fifteen months or so, the average child has a vocabulary of fifty
words or more.
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Entities: daddy, apple, dog, shoes, ball, car, book, etc. (the most)
Properties: hot, more, etc.
Actions: see, eat, etc.
Personal-social: hi, bye, etc.
A “typical” profile for vocabulary development:
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18 months: 50 words
From 18 months to 6 years: 10 words per day
6 years: 14,000 words
From 6 years to 17 years: up to 20 words per day
17 years: 60,000 words
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Morphological development
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Because English has many examples of irregular inflection, children
sometimes begin by simply memorizing inflected words on a case-bycase basis.
When they subsequently observe the generality of -s as a plural marker
and -ed as a past tense marker, they sometimes use these suffixes for
the irregular forms - overgeneralizations or overregularizations.
Stage
Affix acquisition
Examples
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Case-by-case learning
PL: boys, men
PAST: walked, ran
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Overuse of general rule
PL: mans
PAST: runned
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Mastery of exceptions to the
general rule
PL: men
PAST: ran
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Semantic development
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Under and over-extensions:Young children often use words in ways
that are too narrow or too broad.
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bottle used only for plastic bottles;
teddy used only for a particular bear;
dog used for lambs, cats, and cows as well as dogs;
kick used for pushing and for wing-flapping as well as for kicking.
Q: Is every ball on a box?
A (preschooler): No, one of the boxes doesn’t have a ball on it.
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Syntactical development
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During the second year, word combinations begin to appear.
• Novel combinations appear sporadically as early as 14 months.
• At 18 months, 11% of parents say that their child is often combining
words, and 46% say that (s)he is sometimes combining words.
• By 25 months, almost all children are sometimes combining words,
but about 20% are still not doing so "often.”
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A notable feature of children’s two-word utterance is that they almost
always exhibit the appropriate word order.
All wet
See baby
Dry pants
I sit
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Syntactical development
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In the early multi-word stage (also called the telegraphic stage), most
grammatical/functional morphemes are missing.
Chair broken.
Daddy like book.
What her name?
Man ride bus today.
Car make noise.
I good boy.
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In the telegraphic stage, quite elaborate types of phrase structure
emerge:
a head and a complement (like book, ride bus),
a modifier (good)
full-fledged sentences
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Universal grammar
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Systematic errors in child language that cannot be attributed to the
language it is learning can be attributed to possible human grammars
(found elsewhere in the world/time)
A my pencil (Greek)
Tickles me (Chinese)
I don’t want no milk (Spanish)
Who do you think who is in the box (German)
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These grammars are not available in the environment but come from
inside: Universal Grammar, the totality of possible human language
structures.
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Some errors never happen - not allowed by the universal grammar.
“Ask Jabba if the dog that is sitting on the bench is happy?”
• Is the dog that __ sitting on the bench is happy? (not a single kid did
this)
• Is the dog that is sitting on the bench __ happy?
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Language is innate
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There is a set of universal principles, like the principle of structure
dependence, that all languages obey.
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The differences among languages can be described by about a few
dozen of parameters.
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Learning a language is to fix the values of the parameters - by
unlearning all other possible languages.
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Evidence from the study of the brain and the study of diseases and
other afflictions supports the conclusion that language is innate.
• Specialization of brain areas for language
• Systematic correlation between impairment of certain linguistic
abilities and specific areas of brain injury
• These findings will be reviewed later in the semester
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