L1 acquisition of morphology and syntax

LING 101 • Lecture outline M Oct 25

• L1 acquisition of morphologyand syntax

Background reading:

• CL Ch 9, §1, “The study of language acquisition”• CL Ch 9, §4, “Morphological development”• See also: CL Ch 9, §5, “Syntactic development”

1

1. L1 acquisition: Context and key ideas

Review from our phonology acquisition discussion:

• Adults can speak and understand their native language(s) because they have a lexicon and mental grammar of that language

- lexicon —

- mental grammar —

2




- lexicon — where sounds, meaning, and other unpredictable information are stored for each word or morpheme

- mental grammar — rules and principles that handle predictable / systematic patterns, including phonology, morphology, and syntax

3



• How does a child acquiring a native language (first language; L1) get to this target adult state for morphology and syntax?

→ L1 is the abbreviation for first or native language(s): language(s) acquired when no previous language has been acquired

4


• Linguists use the term acquisition rather than learning for children’s language development: Why?

5


• Linguists use the term acquisition rather than learning for children’s language development: Why?→ L1 (first-language) acquisition is different from

learning a skill (more on this next time)

• Why is child language acquisition much more connected to descriptive grammar / mental grammar than it is to prescriptive grammar?

6


• Why do linguists use the term acquisition rather than learning for children’s language development?→ L1 (first-language) acquisition is different from

learning a skill (more on this next time)

• Why is child language acquisition much more connected to descriptive grammar / mental grammar than it is to prescriptive grammar?

L1 acquisition is about how a child’s → mental grammar uses the language data in the environment to develop a language system

7



• A child in the process of acquiring an L1 grammar goes through different stages of development- These stages reflect intermediate mental

grammars on the way to the adult grammar

• A child often shows variable behavior- A rule may be applied only some of the time- Multiple versions of a rule may be in use

• But we can still find a great deal of systematicity in children’s language behavior

8

2. Morphological development: Overview

• What are some aspects of morphology that children need to acquire?

Are these a matter for the lexicon or for the mental grammar?- The morphemes

- Word-formation rules

9


• What are some aspects of morphology that children need to acquire?

Are these a matter for the lexicon or for the mental grammar?- The morphemes

• stored in lexicon

- Word-formation rules• learned/stored in lexicon with relevant affix• but: applied by the mental grammar

10


• Two strong sources of evidence that children are constructing a mental grammar as they acquire their language come from morphology:- overgeneralization

(also known as overregularization)

- productive use of morphology (wug-tests)

11

3. Overgeneralization

• Here is a common pattern in children at three different stages of development (younger older):→

Stage 1

show showed go went

Stage 2

show showed go goed

Stage 3

show showed go went

- What happened? Why did the child’s language ability seem to “go backward”?

12


• Does a child hear forms like goed (or mans, or bringed) in the adult speech community? No! - Why does the child produce such forms, often

after a stage with the correct forms?

13


This is evidence for morphological rules!

• At first, the child stores each form (present/past, singular/plural, etc.) separately in the lexicon

• Then, the child develops a morphological rule

• We know this because the child sometimes applies iteven to irregular forms — overgeneralization- The adult lexicon lists roots that are irregular

and should not undergo the rule- The child has to learn these exceptions!

14


• How we analyze what the child is doing

Stage 1show

lexically listedshowed

lexically listedgo

lexically listedwent

lexically listed

Stage 2show


formed by rulego

lexically listedgoed

formed by rule

Stage 3show


formed by rulego

lexically listedwent

lexically listed

- The past-tense word-formation rule is (temporarily) overgeneralized to the root /gow/

15

4. Productive use of morphology

• Children perform quite well at tasks like these: - This is a wug. Now there is another one.

There are two of them! There are two ___. - What would we call someone who crushes things?

Someone who crushes things is a ___.

• Children can create morphological forms they have never heard before, using familiar or “new” words- What does this show us about a child’s

developing mental grammar?

16

4. Productive use of morphology

• Children perform pretty well at tasks like these: - This is a wug. Now there is another one.

There are two of them! There are two ___. - What would we call someone who crushes things?

Someone who crushes things is a ___.

• Children who can complete these tasks have the relevant inflectional and derivational morphological rules in their mental grammar

• See the original wug-test article (very accessible):

Berko [Gleason], Jean. 1958. The child’s learning of English morphology. Word 14: 150-177. [PDF file]

17

http://childes.psy.cmu.edu/topics/wugs/wugs.pdf

5. Content and function morphemes

A useful distinction in morphology (and syntax):

• Content morphemes (also called lexical morphemes) have real-world meaning- N, V, A- Derivational affixes

• Function morphemes (also called nonlexical or grammatical morphemes) have grammar-related meaning- Det, P, auxiliary verbs, ...- Inflectional affixes

18


• The first morphemes acquired are typically content morphemes

• Function morphemes often have a typical developmental sequence in a given language- Why?

Where does this sequence come from?

19


• Function morphemes: Typical developmental sequence

1. -ing 5. past tense -ed2. plural -s 6. 3rd person singular -s3. possessive ’s 7. auxiliary be4. the, a (CL, Table 9.12, p 365)

• Compare: Typical relative frequency in parent speech1. the, a 5. possessive ’s2. -ing 6. 3rd person singular -s3. plural -s 7. past tense -ed4. auxiliary be (CL, Table 9.13, p 366)

• Does frequency in parent speech predict acquisition order?20


• Frequency of function morphemes in adult speech does not predict how early they will be acquired!→ It’s not just learning what you hear the most...

• What factors do seem to predict early acquisition?- Occurs frequently at the end of the utterance- Forms a syllable on its own- Not a homophone- Behavior is regular — it has few exceptions- Allomorphic invariance (one sound shape)- Has a clearly discernable semantic function

21

6. Syntactic development: Overview

• What are some aspects of syntax that children need to acquire?

Are these a matter for the lexicon or for the mental grammar?- The X' schema parameters (specifier L or R?

head initial or final?)- Complement options (for each head)- Transformations

22


• What are some aspects of syntax that children need to acquire?

Are these a matter for the lexicon or for the mental grammar?- The X' schema parameters (specifier L or R?

head initial or final?) | mental grammar- Complement options (for each head) | lexicon- Transformations | mental grammar

23


• Syntactic development also proceeds in stages

• Examples:- Stages in utterance length- Stages in development of transformations

24

7. Development of utterances

The one-word stage (12 to 18 months)

• One-word utterances are used to express the meaning of a whole sentence

• Some examples from A (my daughter):More (‘I want more milk’)Foot (‘My foot is stuck’/’Get my foot out’)Leaf (‘That’s a leaf’/’I see a leaf’)Mama (‘Mama should do it’)Note: Interpretations of the child’s intended meaning are

based on the context of the utterance

25


The two-word stage (a few months later)

• Words very often lack inflection at this stage - Sometimes, children treat adult phrases as

words in this stage (A had ‘V-it’ for transitive verbs)

• Some examples from A:More crackers (‘I want more crackers’) said as [tatɹz]

That bicycle (‘That’s a bicycle’)Papa eat-it (‘Papa should eat it’)Duck head (‘I have a duck on my head’) don’t ask! :)

Mama up (‘Mama should pick me up’)26


The two-word stage

• Do children have syntactic categories in the two-word stage?- How could we test this? Can we tell?

• Word order mostly matches adult language- But children may learn word order verb by verb

at first (before generalizing their X'-schema)

27


The telegraphic stage (approx. age 2)

• What morpheme type is missing? (Lexical / function?)

- From CL, p 370 Chair broken.Man ride bus today.Car make noise.

- From A Eat-it orange fork mouth.Mama draw big blue O.

28


The telegraphic stage (approx. age 2)

• What morpheme type is missing? | function morph.

- From CL, p 370 Chair broken.Man ride bus today.Car make noise.

- From A Eat-it orange fork mouth.Mama draw big blue O.

• Once the telegraphic stage begins, further development is very rapid (see CL, Table 9.19, pp 371-2)

29


• One fact about individual children that is often reported in research on child language is the child’s MLU, or mean length of utterance- This can be measured in words or morphemes

30


• Why might MLU be more useful than chronological age in comparing children?

31


• Why might MLU be more useful than chronological age in comparing children?- Children’s development follows a typical

sequence, but the age at which each child reached a certain stage can vary by months

• Can MLU help indicate when a child has left the telegraphic stage and become more adult-like? (What should happen to MLU at this point?)

32


• Why might MLU be more useful than chronological age in comparing children?- Children’s development follows a typical

sequence, but the age at which each child reached a certain stage can vary by months

• Can MLU help indicate when a child has left the telegraphic stage and become more adult-like? (What should happen to MLU at this point?)- MLU measured in morphemes should increase

when inflectional affixes start to appear!

33

8. Later development: Movement

• The Inversion rule: How does this develop for English-acquiring children? Stages:a. Questions signaled by intonation onlyb. A relatively rare pattern: Can he can look?→ What rule does this child’s grammar have?

c. Adult-like application of Inversion

• Some children pass through a stage where they can apply Inversion...except when they have to apply Wh Movement too

34


• Draw a tree and apply the appropriate rules for this wh question in the adult grammar of English:What do you think is in the box? - Hint: How many TPs/CPs do we have here?

35


• Draw a tree and apply the appropriate rules for this wh question in the adult grammar of English:What do you think is in the box? - Hint: How many TPs/CPs do we have here?

Deep structure (‘zero’/’silent’ C in embedded clause):

C NP T V C NP T V [----PP-----]+Q you -Pst think [CP Ø [TP what -Pst is in the box]

36


• Deep struc.:

37


• Suppose we want to study this type of wh question in child language. How might we collect data?- Naturalistic vs. experiment studies (what are the

pros and cons?)

- Here is a video of a wh-question study

38

https://www.youtube.com/watch?v=MZiVOyhFu6c


• Consider the syntax of the child in the video:

What do you think what is in the box?

- What does this child’s current Wh Movement ruleseem to be?

39


• Consider the syntax of the child in the video:

What do you think what is in the box?

- What does this child’s current Wh Movement ruleseem to be?

- The child seems to move the wh phrase to the specifier of CP, but leaves a copy of it behind instead of leaving a trace (t) in the structure!This particular child pattern is not necessarily common, but is sometimes observed

40

9. Implications

• In both morphology and syntax, we see children...- applying rules of the mental grammar - in non-adult-like ways

• This is important evidence that part of L1 acquisitionis developing linguistic rules- Children applying non-adult-like rules can’t be

just copying from their language environment- And yet, their productive use of these rules

shows that their mental grammar is involved

41

L1 acquisition of morphology and syntax

Documents

Transcript of L1 acquisition of morphology and syntax