Transcript PSY 369: Psycholinguistics

PSY 369: Psycholinguistics
Language Acquisition III
Brief outline
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Continue describing the acquisition of language:
syntax and morphology
Some topics in the innateness (nativism vs. empiricist)
debate:
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What kind of feedback (teaching) do kids get?
Is there a critical period for language?
Language explosion continues
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The language explosion is not just the result of simple
semantic development; the child is not just adding
more words to his/her vocabulary.
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Child is mastering basic syntactic and morphological
processes.
Language explosion continues
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Syntax
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Mean length of utterance (MLU) in morphemes
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Take 100 utterances and count the number of
morphemes per utterance
Daddy coming. Hi, car. Daddy car comed. Two car outside. It
getting dark. Allgone outside. Bye-bye outside.
# morphemes: 3, 2, 4, 3, 4, 2, 2
‘-ing’ and ‘-ed’ separate morphemes
‘allgone’ treated as a single word
MLU = morphemes/utterances
= 20/7 = 2.86
Language explosion continues
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Syntax
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Mean length of utterance (MLU) in morphemes
Language explosion continues
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Proto-syntax (??)
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Holophrases (around 1-1.5 years)
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Single-word utterances may be used to express more than the
meaning usually attributed to that single word by adults
“dog”
might refer to the dog is drinking water
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Typically idiosyncratic, but some conventional/common (e.g.,
indicate the existence of an object, request recurrence of object
or event)
Often combined with intonation or gesture
Controversial claim: May reflect a developing sense of syntax,
but not yet knowing how to use it (e.g., see Bloom, 1973)
Language explosion continues
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Syntax
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Roger Brown (1973) proposed 5 stages
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Stage 1: Telegraphic speech (MLU ~ 1.75; around 24 months)
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Children begin to combine words into utterances
Limited to a small set of semantic relations (e.g., nomination,
recurrence, attribution, possession [see table 10.3 for examples])
Debate: learning semantic relations or syntactic (position rules)
 “baby sleep” agent+action or Noun Verb
Children in telegraphic speech stage are said to leave out the ‘little
words’ and inflections:
 e.g. Mummy shoe NOT Mummy’s shoe
 Two cat NOT two cats
Language explosion continues
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Syntax
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Roger Brown (1973) proposed 5 stages
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More than two words
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Stages 2 through 5
 Stage 2 (MLU ~2.25)
 begin to modulate meaning using word order (syntax)
 Modulations for number, time, aspect
 Gradual acquisition of grammatical morphemes (“-ing”, “-s”
 Later stages reflect generally more complex use of syntax (e.g.,
questions, negatives)
How do kids learn the syntax?
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Innateness accounts
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Semantic bootstrapping
Learned accounts
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Acquired from the linguistic input from the environment
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It is in the stimulus
How do kids learn the syntax?
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Innateness account
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Pinker (1984, 1989)
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Semantic bootstrapping
Child has innate
knowledge of
syntactic categories
Child learns the
and linking rules
meanings of
some content words Child constructs some
semantic representations
Child makes guesses
of simple sentences
about syntactic structure
based on surface form
and semantic meaning
How do kids learn the syntax?
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“It is in the stimulus” accounts (e.g. Bates, 1979)
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Speech to children is not impoverished (Snow, 1977)
Children learn grammar by mapping semantic roles (agent,
action, patient) onto grammatical categories (subject, verb,
object)
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In all languages there are multiple potential cues indicating
semantic/syntactic relations (e.g., word order, case marking)
Similar words occur in similar linguistic contexts
Acoustic information (e.g., prosody) may provide syntactic cues
Children do not need innate knowledge to learn grammar
Acquiring Morphology
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Morphology
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Typically things like inflections and prepositions start around
MLU of 2.5 (usually in 2 yr olds)
Remember the Wug experiment (Berko-Gleason, 1958)
Acquiring Morphology
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Morphology
This person knows how to rick. She did the same thing yesterday.
Yesterday she ________.
Typically children say that she “ricked.”
Acquiring Morphology
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Morphology: order of acquisition
Age (yrs)
Morpheme
Example(s)
2
Present progressive
I driving
2
Articles
A dog, the doctor
2
Plural
Balls
2
Uncontractible Copula
He is asleep, am, are
3
Third person singular
He wants an apple
3
Full progressive
Be + ing, I am singing
3
Regular past tense
She walked
Acquiring Morphology
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Children sometimes make mistakes.
My teacher holded the baby rabbits.
Yes
She holded the baby rabbits.
No, she holded them loosely.
Did you say your teacher held the baby rabbit?
What did you say she did?
Did you say held them tightly?
Acquiring Morphology
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Children sometimes make mistakes.
My teacher holded the baby rabbits.
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This is ungrammatical in the adult language
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Shows that children are not simply imitating
In this case, what they produce something that is not in their
input.
Acquiring Morphology
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Children sometimes make mistakes.
My teacher holded the baby rabbits.
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Why do they make errors like these?
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In the case at hand, we have what is called overregularization
The verb hold has an irregular past tense form, held
Because this form is used, the regular past tense-- that with ed-- is not found (*hold-ed)
Acquiring Morphology
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The case of verb past tense:
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Regular verb forms require no stored knowledge of the
past tense form (wug test)
 Past tense is accomplished by applying a past tense
rule (e.g., add -ed) to the verb stem
With irregular verbs something must be memorized
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Examples:
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Horton heared a Who
I finded Renée
The alligator goed kerplunk
Acquiring Morphology
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The case of verb past tense:
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Stages in the acquisition of irregular inflections
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With regular verbs, the default form -ed is used
With irregulars, lists associating the verb with a
particular form of the past tense have to be memorized:
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Past tense is -t when attached to leave, keep, etc.
Is -> was
Dig -> dug
Has -> had
Acquiring Morphology
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Stages in the acquisition of irregular inflections
time
Step
1
2
3
4
5
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Description
No inflection
Adult form
Overregularization
Transition
Adult form
Noun
Man
Men
Mans
Mens
Men
Examples
Verb
Adjective
Go
Bad
Went
Worse
Goed
Badder
Wented Worser
Went
Worse
On the face of it, learning these morphological quirks follows a
peculiar pattern:
 Early: correct irregular forms are used
 Middle: incorrect regular forms are used
 Late: correct forms are used again
Memory & Rules
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Why do we find this type of pattern?
 Memory and rules
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The use of overregularized forms starts at around the
same that that the child is beginning to apply the default
-ed rule successfully
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Early: All forms-- whether regular or irregular-- are
memorized
Middle: The regular rule is learned, and in some cases
overapplied
Late: Irregulars are used based on memory, regulars use
the rule (the idea is that if the word can provide its own
past tense from memory, then the past tense rule is
blocked)
Memory & Rules
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Why do we find this type of pattern?
 Memory and rules
 Other accounts
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Maratsos (2000) – frequency explanation
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It is possible to predict which verbs will be subject to
overregularization
 The more often an irregular form occurs in the input, the
less likely the child is to use it as an overregularization
 This is evidence that some part of overregularization
occurs because of memory failures
 Something about irregulars is unpredictable, hence
has to be memorized
What kind of “teaching” do kids get?
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If language is learned (and
not innate), how do kids do
it?
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What kind of feedback do
they get?
Claim: Positive evidence is
not sufficient for learning a
language.
What kind of “teaching” do kids get?
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Are the kids even aware of mistakes?
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The children are apparently aware of the fact that their
forms are strange:
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Parent: Where’s Mommy?
Child: Mommy goed to the store
Parent: Mommy goed to the store?
Child: NO! Daddy, I say it that way, not you
Positive and negative evidence
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What kind of feedback is available for learning?
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Positive evidence: Kids hear grammatical
sentences
Negative evidence: information that a given
sentence is ungrammatical
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Kids are not told which sentences are ungrammatical
(no negative evidence)
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Let’s consider no negative evidence further…
What kind of “teaching” do kids get?
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How much Positive Evidence is there?
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Estimated 5000 – 7000 utterances a day
Between ¼ and 1/3 are questions
Over 20% are not “full” adult sentences (typically Noun
or prepositional phrases)
Only about 15% have typical English SVO form
Roughly 45% of all maternal utterances began with one
of 17 words (e.g., “what”, “that”, “it”, “you”)
Cameron-Faulkner, et al (2003)
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So what kids do hear may be somewhat limited.
Negative evidence
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Negative evidence could come in various
conceivable forms.
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“The sentence Bill a cookie ate is not a sentence in
English, Timmy. No sentence with SOV word order
is.”
Upon hearing Bill a cookie ate, an adult might
 Not understand
 Look pained
 Rephrase the ungrammatical sentence
grammatically
Kids resist instruction…
McNeill (1966)
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Child: Nobody don’t like me.
Adult: No, say ‘nobody likes me.’
Child: Nobody don’t like me.
[repeats eight times]
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Adult: No, now listen carefully; say ‘nobody likes me.’
Child: Oh! Nobody don’t likes me.
Kids resist instruction…
Cazden (1972) (observation attributed to Jean Berko Gleason)
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Child: My teacher holded the baby rabbits and we patted them.
Adult: Did you say your teacher held the baby rabbits?
Child: Yes.
Adult: What did you say she did?
Child: She holded the baby rabbits and we patted them.
Adult: Did you say she held them tightly?
Child: No, she holded them loosely.
So there doesn’t seem to be a lot of explicit negative evidence, and
what there is the kids often resist
Negative evidence via feedback?
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Do kids get “implicit” negative evidence?
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Do adults understand grammatical sentences and not understand
ungrammatical ones?
Do adults respond positively to grammatical sentences and
negatively to ungrammatical ones?
Negative evidence via feedback?
Brown & Hanlon (1970):
Case study of “Adam” - looked at things that were said to
him by adults, and what he said to them
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Adults understood 42% of the grammatical sentences.
Adults understood 47% of the ungrammatical ones.
Adults expressed approval after 45% of the
grammatical sentences.
Adults expressed approval after 45% of the ungrammatical
sentences.
Suggests that there isn’t a lot of good negative evidence.
In a way, it’s moot anyway…
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One of the striking things about child language is how few
errors they actually make.
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For negative feedback to work, the kids have to make the errors
(so that it can get the negative response).
But they don’t make enough relevant kinds of errors to determine
the complex grammar.
Pinker, Marcus and others, conclude that much of this stuff
must be innate.
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But this isn’t the only view. There is an ongoing debate about
whether there are rules, or whether these patterns of behavior
can be learned based on the language evidence that is available
to the kids
Critical (sensitive) periods
Critical (sensitive) periods
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Certain behavior is developed more quickly
within a critical period than outside of it. This
period is biologically determined.
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Examples:
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Imprinting in ducks (Lorenz, ; Hess, 1973)
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Ducklings will follow the first moving thing they see
Only happens if they see something moving within the first
few hours (after 32 hours it won’t happen) of hatching
Binocular cells in humans
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Cells in visual system that respond only to input from both
eyes.
If these cells don’t get input from both eyes within first year
of life, they don’t develop
Critical (sensitive) periods
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Certain behavior is developed more quickly
within a critical period than outside of it. This
period is biologically determined.
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Some environmental input is necessary for normal
development, but biology determines when the
organism is responsive to that input.
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That “when” is the critical period
Critical period for language
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Lenneberg (1967) proposed that there is a critical
period for human language
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It assumes that language acquisition must occur
before the end of the critical period
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Estimates range from 5 years up to onset of puberty
Evidence for critical period for language
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Feral Children
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Children raised in the wild or with reduced exposure to
human language
What is the effect of this lack of exposure on language
acquisition?
Two classic cases
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Victor, the Wild Boy of Aveyron
Genie
Victor, The Wild Boy of Aveyron
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Found in 1800 near the outskirts of Aveyron, France
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Estimated to be about 7-years-old
Considered by some to be the first documented case of autism
Neither spoke or responded to speech
Taken to and studied by Dr. Jean-Marc-Gaspard Itard, and
educator of deaf-mute and retarded children
Never learned to speak and his receptive language ability was
limited to a few simple commands.
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Described by Itard as “an almost normal boy who could not speak”
Genie
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Found in Arcadia, California in 1970, was not
exposed to human language until age 13.5.
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Raised in isolation a situation of extreme abuse
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Genie could barely walk and could not talk when
found
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Dr. Susan Curtiss made great efforts to teach her
language, and she did learn how to talk, but her
grammar never fully developed.
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Only capable of producing telegraphic utterances
(e.g. Mike paint or Applesauce buy store)
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Used few closed-class morphemes and function
words
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Speech sounded like that of a 2-year-old
Genie
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By age of 17 (after 4 years of extensive training)
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Vocabulary of a 5 year old
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Poor syntax (telegraphic speech mostly)
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Examples
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Mama wash hair in sink
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At school scratch face
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I want Curtiss play piano
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Like go ride yellow school bus
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Father take piece wood. Hit. Cry.
What Do These Cases Tell Us?
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Suggestive of the position that there is a critical
period for first language learning
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If child is not exposed to language during early childhood
(prior to the age of 6 or 7), then the ability to learn syntax will
be impaired while other abilities are less strongly affected
Not uncontroversial: Victor and Genie and children like them
were deprived in many ways other than not being exposed to
language
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Genie stopped talking after age 30 and was institutionalized
shortly afterward (Rymer, 1993)
Effects of the Critical Period
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Learning a language;
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Under c. 7 years: perfect command of the language possible
Ages c. 8- c.15: Perfect command less possible
progressively
Age 15-: Imperfect command possible
In some special cases, we are given a window on the
nature of the critical period
Effects of the Critical Period
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Learning a new language
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What if we already know one language, but want to learn
another?
Effects of the Critical Period
Johnson and Newport (1989)
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Native Chinese/Korean speakers moving to US
Task: Listen to sentences and judge whether
grammatically correct
Age and Second-language acquisition
mean score on
English grmmar test
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280
270
260
250
240
230
220
210
200
native
3 to 7
8 to 10
age of arrival
11 to 16
17 to 39