Week 4. Null subjects (and some more root infinitives)

1
GRS LX 700Language Acquisition andLinguistic
Theory

• Week 4. Null subjects(and some more root
  infinitives)

2
Null subjects (in English)

• Until after around 2 years old, kids will often
  omit subjects
• Drop bean.
• Fix Mommy shoe.
• Helping Mommy.
• Want go get it.
• Why?

3
Null subjects

• Lots of languages allow you to drop the subject.
• Italian, Spanish the verb generally carries
  enough inflection to identify the person, number
  of the subject.
• Chinese where the subject is obvious from
  context it can be left out.
• Not in English though Lets talk about Bill.
  Left. Bought groceries. Dropped eggs.

• On the view that kids know language, but are just
  trying to figure out the specific details
  (principles and parameters), one possibility is
  that they always start out speaking Italian (or
  Chinese) until they get evidence to the contrary.
• Null subjects are grammatical for kids

4
Null subjects

• Kids do tend to speak in short sentences. There
  seem to in fact be identifiable stages in terms
  of the length of the kids sentences (one-word
  stage, two-word stage, multi-word stage), often
  measured in terms of MLU (mean length of
  utterance) which roughly corresponds to
  linguistic development.

• Perhaps the kids just trying to say a three-word
  sentence in a two-word window, so something has
  to go.
• That is, some kind of processing limitation.

5
Subject vs. object drop
A E S
Subject 57 61 43
Object 8 7 15
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Null subjects

• Subjects (in a non-null subject language like
  English) are way more likely to be dropped than
  objects. Theres something special about
  subjects.
• Makes a processing account more difficult to
  justify.

• Bloom (1990) made some well-known proposals about
  how the null subject phenomenon could be seen as
  a processing issue, and tried to explain why
  subjects are the most susceptible to being
  dropped.
• See also Hyams Wexler (1993) for a reply.

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Null subjects vs. time

• Null subjects seem to be pretty robustly confined
  to a certain portion of linguistic development.
  Theres a pretty sharp dropoff at around 2.5 or
  3.
• Hamanns Danish kids illustrate this well.

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Why cant English kids really be speaking Italian?

• In Italian, subjects can be dropped (but need not
  be), in English, they cant be dropped at all.
• So since having subjects is consistent with
  Italian, whats going to signal to the kid that
  theyve got the wrong kind of language?
• A subset problem.
• Possible solution? Expletive it and there.

• In Italian, null subjects are allowed wherever a
  subject pronoun would be, including embedded
  finite clauses (I know that he has left) and
  finite root questions (What has he bought?).
• In Kid English, null subjects never show up in
  these environments. It doesnt seem so much like
  Italian.

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Ok, maybe these kids are speaking Chinese

• In adult Chinese, subjects can also be omitted.
• In Italian, Spanish, the allowability of null
  subjects was taken to be tied to the verbal
  agreement. Something about the rich agreement
  licenses null subjects.

• In Chinese, there is no agreement morphology, so
  that isnt whats allowing null subjects.
• Proposal What allows argument omission in
  Chinese is a form of topic drop. They are allowed
  roughly when they are old information,
  recoverable.

10
Speaking Chinese?

• Suppose that these are parameters.
• Pro-drop for the Italian/English difference.
• Topic-drop for the Chinese/English difference.
• Kid English isnt Pro-drop.

• In Topic-drop languages, subjects arent
  particularly privileged.
• Subjects are often old information, but when
  objects are old information, they too can be
  dropped.

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Not speaking Chinese

• Weve already seen that Kid English
  overwhelmingly drops subjects, not objects.
• 33 subjects,4 objects(Wang et al 1992)
• Kid English looks like English with some extra
  null subjects.

• But Kid Chinese drops even more subjects and lots
  more objects.
• 47 subjects,23 objects.
• Kid Chinese looks like Chinese with maybe some
  extra null subjects.

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Parameters are quick

• And recall that Italian allows null subjects in
  embedded clauses, wh-questions, etc.
• Kid Dutch and French have practically no null
  subjects in wh-questions.
• Kid Italian has something like 56 null subjects
  in wh-questions.

• If Chinese/Dutch is distinguished by
  topic-drop and Italian/English is
  distinguished by pro-drop, the kids already
  know what theyre trying to speak by the time
  were testing them.

13
Processing accounts?

• Kids have severely limited processing power, and
  so they leave off subjects to ease the load.
  (Bloom 1990)
• In favor
• Length limitations even in imitations
• Kids omit things other than subjects
• Some kids dont eliminate subjects, only reduce
  their frequency.

14
Processing accounts

• Contra? Hyams points out
• Build houseCathy build house
• Go nurseryLucy go nursery
• Kathryn want build another house.
• Bloom So, no absolute limit on length, only a
  tendency to reduce length.

15
Bloom (1990)

• Bloom (1970) found
• negated sentences tend to lack subjects more
  frequently then non-negated sentences.
• Bloom (1990)
• Hypothesis sentences without subjects will have
  longer VPs than sentences with subjects.
• Looked at past tense verbs and cognitive states
  (need) to avoid any confusion with imperatives.

16
Bloom (1990)

• VP length (words from verb to the end) counted
  for sentences with and without subjects.
• Results Mean length of VP in sentences with
  subjects were (statistically) significantly
  shorter than those without.
• E.g., Adam 2.333 with, 2.604 without.

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Bloom (1990)

• In fact, long subjects (lexical subjects),
  short subjects (pronouns), and null subjects
  correlated with an increase in VP length as well.

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Bloom (1990)

• And why are subjects dropped more frequently than
  objects?
• Two possibilities?
• Subjects tend to be given (old) information (low
  informativeness, more expendable)
• Maybe processing saves the heaviest load for
  last

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Hyams Wexler (1993)

• Blooms (1990) approach (processing) cant be
  right either.
• The difference between subjects and objects is
  big, and only rate of subject drop changes.
• Adam Eve both drop around 40-50 of their
  subjects in an early stage, and in a later stage
  are down to 15-30meanwhile their rate of object
  drop stays around 5-10.

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Hyams Wexler (1993)

• Informativeness?
• All else being equal, the ratio of missing
  subjects to specific subjects should be equal to
  the ratio of missing objects to specific
  objects.
• Turns out that kids drop specific subjects about
  twice as often (Adam 52) as they drop specific
  objects (Adam 21).

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Hyams Wexler (1993)

• Considering Italian adults, we find exactly the
  same correlation Bloom reported for English kids
  VP seems to be longer where there is null
  subject, shorter with a pronoun, and shorter
  still with a lexical subject.

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Hyams Wexler (1993)

• Regardless of why the correlation holds, if it is
  a processing deficiency in kids, what is it for
  the Italian adults?
• Seems like kids act like theyre speaking a
  language where the null subject is a grammatical
  option. Note might be slightly different from a
  null subject language though. Point dropping
  subjects is grammatical for these kids, not an
  error.

23
Hyams Wexler (1993)

• Output omission model predicts ratio of overt
  lexical subjects to overt pronouns should
  increase over time.
• Pronouns are easier, theyll survive. Lexical
  subjects are harder, theyll be dropped. Initial
  advantage to visible pronouns.
• Grammatical omission model predicts ratio of
  overt lexical subjects to overt pronouns should
  decrease over time.
• If null subjects are a form of pronoun for kids,
  they will dilute the pool, putting visible
  pronouns at an initial disadvantage.

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Hyams Wexler (1993)

• We find Ratio of overt lexical subjects to overt
  pronouns decreases over time
• Adam goes from about 31 in favor of lexical
  subjects (during subject drop stage) to 12
  (after subject drop stage).
• When hes dropping subjects, they are coming out
  of the pronoun pilethe number of lexical
  subjects is staying about the same across
  development.

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Hyams Wexler (1993)

• Ok, so maybe pronouns are more difficult than
  lexical nouns? (Doesnt fit well with the length
  of VP result, but maybe?)
• Problem is kids show a steady level of object
  pronouns throughout this time periodand output
  omission model doesnt have anything to say about
  subject vs. object.

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Hyams Wexler (1993)

• Basic conclusion
• Null subjects dont seem to arise in child
  language solely due to processing difficulty.
• Rather, they seem to be allowed in the child
  grammar.
• This allows a distinction between subject (high
  rate of omission) and object (low rate of
  omission)
• Explains the tradeoff between null subjects and
  pronouns (and the VP length/subject correlation)
  if the principles governing availability of
  subject drop are similar to those at work in
  Italian.

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So what allows null subjects?

• Heres where we start to tie in to other
  properties of that age.
• Notice that in English (a non-null subject
  language) you can have a grammatical null subject
  in one context
• I want Ø to have a fire drill
• Ø to have a fire drill would make my day.

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So what allows null subjects?

• Subjects of infinitives can be null.
• Kids at the age where subjects are often missing
  often use infinitive verb forms.
• Perhaps thats the key Since kids can use
  infinitives where adults cant (main clause main
  verb), this allows them to use null subjects in
  those sentences as a side effect.

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Proportion of null subjects in finite and
non-finite clauses
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Null subjects

• Null subject parameter(s) is/are not initially
  mis-set (kids dont all start off speaking
  Italian or Chinesecontra Hyams 1986, 1992)
  rather, child null subjects are (at least in
  part) due to the availability of non-finite verbs
  (the OI stage).
• Most null subjects are licensed by being the
  subject of a nonfinite verb (i.e. PRO)
• But there are still some null subjects with
  finite verbs Well return to this.

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Null subjects and C

• Crisma (1992) French kids typically (1/114 1
  vs. 407/100241) do not produce null subjects
  with a wh-phrase.
• Valian (1991) English kids typically (9/5522)
  do not produce null subjects with a wh-phrase.
• Poeppel Wexler (1993) German kids typically
  exclude null subjects from post-V2 position.

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Null subjects and C

• It looks like If the kid shows evidence of CP
  (wh-words, V2), then the kid also does not drop
  the subject.
• Rizzis idea
• A discourse-licensed null subject is available
  only in the highest specifier in the tree
  (topic-drop).
• Axiom CProot
• Kids dont get the axiom until between 2-3
  years old.

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Truncated trees

• The result (of not having CProot) is that kids
  are allowed to have truncated structurestrees
  that look like adult trees with the tops chopped
  off.
• Importantly The kids dont just leave stuff
  outthey just stop the tree early. So, if the
  kid leaves out a functional projection, s/he
  leaves out all higher XPs as well.

34
Truncation

• If kid selects anything lower than TP as the
  root, the result is a root infinitivewhich can
  be as big as any kind of XP below TP in the
  structure.
• Note in particular, though, it cant be a CP.
• So we expect that evidence of CP will correlate
  with finite verbs.

35
Truncation

• Pierce (1989) looking at French observed that
  there are almost no root infinitives with subject
  cliticsthis is predicted if these clitics are
  instances of subject agreement in AgrS if there
  is no TP, there can be no AgrSP.

36
Truncation

• There is some dispute in the syntax literature as
  to whether the position of NegP (the projection
  responsible for the negative morpheme) is higher
  or lower than TP in the tree.
• If NegP is higher than TP, we would expect not to
  find negative root infinitives.

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Truncation and NegP

• But we do find negative Root Infinitives(Pierce
  1989) in the acquisition of French, negation
  follows finite verbs and preceds nonfinite verbs
  (that isFrench kids know the movement properties
  of finiteness, and thus they have the concept of
  finiteness).

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Truncation and NegP

• So, is TP higher than NegP?
• Hard to say conclusively from the existing French
  data because there are not many negative root
  infinitivesbut further study of child language
  could lead to a theoretical result of this sort
  about the adult languages, if we assume a
  truncation analysis of child language.

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S O Vfin AgrSP?

• Usually (Poeppel Wexler 1993) German kids put
  finite verbs in second position, and leave
  nonfinite verbs at the end.
• Occasionally one finds a finite verb at the end.
• Rizzi suggests we could look at this as an
  instance of a kid choosing AgrSP as root, where
  CP is necessary to trigger V2.
• PW had to basically consider these noise.

40
Truncation and null subjects

• As for null subjects
• If the tree is just a VP, the subject can be
  omitted in its base positionits still in the
  specifier of the root.
• If the tree is just a TP, the subject can be
  omitted from the normal subject positionnote
  that this would be a finite verb with a null
  subject.
• If the tree is a CP and SpecCP is filled (like in
  a wh-question) we expect no null subjects.

41
Null subject languages vs. root infinitives

• Italian seems to show no (or very very few) root
  infinitives. If this is maturation of RootCP
  how could languages vary?
• Rizzi suggests
• In English, V doesnt move
• In French, tensed verbs move to AgrS (I),
  untensed verbs may move to AgrS
• In Italian, all verbs move to AgrS

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Null subject languages vs. root infinitives

• The idea is that a verb in Italian needs to get
  to AgrSit has a feature/property (parametric)
  that marks it as needing to get to AgrS in a
  grammatical sentence. Hence, the kid needs AgrS.
• English verbs have no such need, so the English
  kids have to rely on RootCP to tell them to keep
  going.

43
Null subject languages vs. root infinitives

• Rizzi and Wexler capture NS/OI similarly
• Wexler AgrS does not need a subject in its
  specifier in Italian, so there is no competition
  between AgrS and T, and thus no need for root
  infinitives. AgrS and T are always both there.
• Rizzi AgrS can never be omitted in Italian,
  because the verb needs AgrS to be there. Having
  AgrS implies T. AgrS and T are always both there.

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Back to null subjects vs. Fin

• Bromberg Wexler (1995) promote the idea that
  null subjects with finite verbs arise from a kind
  of topic drop (available to adults in special
  contexts).
• Proposal (Bromberg Wexler)Topic-drop applies
  to Very Strong TopicsKids sometimes take (in
  reality) non-VS topics to be VS topics (a
  pragmatic error)

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Prediction about NS

• RIs have two ways of licensing NSs
• PRO (regular licensing of null subject)
• Topic drop
• Finite verbs have one way to license a NS
• Topic drop
• So We expect more null subjects with root
  infinitives (which we in fact see).
• Cf. Rizzi Subject in highest specifier can
  always be dropped, and RIs also allow PRO. Same
  story, basically.

46
Bromberg, Wexler, wh-questions, and null subjects

• If topic drop is something which drops a topic in
  SpecCP
• and if wh-words also move to SpecCP
• we would not expect null subjects with
  non-subject (e.g., where) wh-questions where the
  verb is finite (so PRO is not licensed).
• Cf. Rizzi Same prediction if you have a CP, a
  subject in SpecTP wont be in the highest
  specifier, so it cant be dropped. One
  difference Rizzi predicts no nonfinite
  wh-questions at all, hence no null subjects at
  all.

47
Bromberg, Wexler, wh-questions, and null subjects

• Finiteness of null/pronominal subjects, Adams
  wh-questions (Bromberg Wexler 1995)

Finite Nonfinite
Null 2 118
Pronoun 117 131
48
Truncation

• Rizzis truncation theory predicts
• No wh-questions with root infinitives
• wh-question ? CP, but
• CP ? IP, and
• IP ? finite verb
• And of course we wouldnt expect null subjects in
  wh-questions if null subjects are allowed (only)
  in the specifier of the root.

49
Truncation?

• Guasti points out that although Bromberg Wexler
  did find null subjects in wh-questions in
  English, English is weird in this respect.
• Arguably, null subjects are precluded from
  wh-questions in most other languages.

50
V2 and wh-null subjects

• German and Dutch have extremely few root
  infinitives when there is anything in SpecCP.
• This does go with Rizzis prediction
• But they are V2 languagesfinite verbs are what
  you find in C, and when SpecCP is filled, there
  must be something in C. Hence, Wexlers
  prediction seems to be
• V2 language ? no wh-question root infinitives
• And this seems closer to accurate, given English.

51
V2 and wh-null subjects

• And yet, Crismas (1992) findings and Hamann
  Plunketts (1998) findings suggest that French
  (not V2) also shows almost no null subjects in
  wh-questions.
• So whats different about English?
• French, Dutch, German basically never have null
  subjects in wh-questions.
• English allows them readily.

52
Adult null subjects(diary drop)

• Both Rizzi and Bromberg Wexler appeal to
  properties of adult language to justify the child
  null subjects.
• BW suggest that topic drop is available in
  English, but only for Very Strong topics, and
  what kids are doing wrong is identifying far too
  many things as VS topics.
• Rizzi suggests that the ability to drop a subject
  in the highest specifier is available in certain
  registers (diary drop) (where presumably
  RootCP is disregarded, or at least relaxed to
  allow RootIP).
• Saw John today. Looked tired.

53
Hamann Plunkett (1998)

• Finite null subjects. Hamann discussed this
  question If null subjects are licensed by RIs,
  what should we say about the null subjects with
  finite verbs? W had previously said topic drop,
  but H showed that Danish kids use of null
  subjects with finite verbs correlated highly with
  the use of RIs in general.
• Thats a problem because topic drop according
  to BW is due to kids mistaking what can be a VS
  topic, and should be independent of Tense/Agr.
  For truncation, though, the same basic mechanism
  is at work creating both finite null subjects and
  RIs.

54
Root infinitives vs. time

• The timing on root infinitives is pretty robust,
  ending around 3 years old.

55
Wexler (2000)

• Are there really lots of null subjects with
  finite verbs in Danish?
• Idea køb-er looks like present tense finite, but
  it could be missing T (hence legitimately license
  NS).
• Agr, Tns køb-er (present) (adult)
• -Agr, Tns køb-e (infinitive) no NS allowed
• -Agr, -Tns køb-e (infinitive) NS allowed
• Agr, -Tns køb-er (present) NS allowed.
• Predicts No NSs with past tense verbs like
  køb-de (since unambiguously Tns, which is the
  thing that prevents NS). True?

56
Hamann (2002) vs. Wexler

• Well, not really vanishingly small
• Jens (20-34 mos.s) 14/42 (33) NS past.
• Anne (18-30 mos.) 13/33 (39) NS past.
• Hamann herself prefers a truncation story to
  account for these finite NS corresponds to
  truncating at TP.
• Yet, dont forget about Swahili, and the
  apparently visible effects of ATOM.

57
Interpretation and functional categories

• A basic premise of Hoekstra Hyams (1998) is
  that tense is a means of connecting between the
  structural meaning and the discourse. Tense
  anchors a sentence in the discourse.
• They propose that the relation between discourse
  (CP) and T must be signaled (to ground an
  utterance), and is signaled by different things
  in different languages.
• Dutch number morphology ? only these have RIs?
• Japanese tense morphology
• Italian, Spanish, Catalan person morphology

58
Underspecification of number?

• HH propose in light of this that whats wrong
  with kids has to do with number specifically. OI
  languages are those where number is crucial in
  the finite inflection.
• HH picked up on something about when these RIs
  seem to be used. It seemed that there are certain
  verbs that showed up in the nonfinite form, but
  others that didnt.

59
Eventivity Constraint

• In particular, it seems that RIs show up only
  with verbs referring to events not with verbs
  referring to states, not with auxiliary verbs.
  Finite verbs seem to have no such restriction.
  Original research on Dutch on French, also
  Russian.
• Eventivity ConstraintRIs are restricted to
  event-denoting predicates.

60
Modal Reference Effect

• The other thing is that RIs often have a modal
  meaning (can, will, must, want to..) (pretty
  dramatic in Dutch, German, French).
• Poeppel Wexler (1993) did give a German example
  from Andreas that showed an RI with seemingly no
  modal meaning (Thorsten Ball haben) if HH are
  right, this was noise.
• Modal Reference EffectWith overwhelming
  frequency, RIs have modal interpretations.

61
English weird

• English doesnt seem to conform to the pattern.
  Ud Deen (1997) found
• plenty of bare stative verbs (EC)
• Man have it
• Ann need Mommy napkin
• Papa want apple
• plenty of non-modal bare verbs (MRE)
• Dutch 86 of RIs have modal meaning. Cf. 3of
  finite forms.
• English 13 of bare forms have modal meaning Cf,
  12 of finite forms..

62
HHs hypothesis

• Number is an inflectional property both of the
  nominal and the verbal system.
• though it arises in the nominal system.
• Missing determiners and RIs are both a symptom of
  underspecified Number.
• Spec-head agreementcommunicates
  number(under)specificationto the verb.

63
HH (1998) BUCLD

• Looked at Niek (CHILDES, Dutch).
• They found that with finite DPs, the verb was
  pretty much always finite too.
• They found that with nonfinite DPs, the verb
  was somewhat more likely to be nonfinite than
  with a finite DP, but still overwhelmingly
  favored finite DPs.
• Only null subjects didnt overwhelmingly favor
  finite V. (NS 45 nonfinite).

64
HH (1998) BUCLD

• All things being equal, we might have expected a
  11 correlation between finite DP subjects and
  finite V, if it were a matter of Spec-head
  agreement. We dont have that. We have a
  one-directional relation.
• If DP is finite, V is finite.
• If V is nonfinite, DP is nonfinite.

65
HH (1998) BUCLD

• In a sense, one setting cares about its partner
  in the Spec-Head relationship, and the other
  setting doesnt.
• Finite V seems not to care whether the subject is
  finite or not.
• Nonfinite V does seem to care, and requires a
  nonfinite subject.
• More specifically, there is a default, and the
  default does not need to be licensed (and
  non-defaults do).
• This goes along with an assumption that either
  the syntax doesnt make person distinctions if
  the morphology doesnt, or that this part of
  checking is really about morphology.

66
HH (1998) BUCLD

• In Dutch, 3sg is default.
• 1sg verb licensed only by a 1sg subject.
• 3sg verb licensed by any old subject.
• In English, 3sg is not the default. Its the one
  marked form.
• 3sg verb licensed only by a 3sg subject.
• bare verb licensed by any old subject.

67
Thus

• The doggie bark.
• He bark
• Doggie sit here.
• Doggie barks.
• Het hondje hier zitten.
• He hier zitten.
• Hondje hier zitten.
• Hondje zit hier.

68
cf. Schütze Wexler

• the English bare form is ambiguous between an
  infinitive and a finite form (HH98101)
• Although stated in different terminology, and
  addressing a slightly different arena of facts,
  the basic concept is the same as that in SW96.
• TA -gt finite (-s)
• T-A, -TA, -T-A -gt nonfinite (stem)
• but A ones will have A properties (e.g. NOM),
  even if just a stem form. Same for T.

69
English bare form ? infinitive

• SW and HH agree that the English bare form
  isnt strictly speaking (necessarily) the true
  infinitive.

70
HH and interpretation

• Claim RIs are interpreted as -realized, the
  contribution of the infinitival morpheme itself.
• Languages with an infinitival morpheme and actual
  RIs should show 100 modal (-realized)
  interpretation with RIs.
• English, with a Ø infinitival morpheme, obscures
  the correlation in practice, we expect only some
  (the actually infinitive) bare forms to be modal.

71
epistemic vs. deontic

• John must leave.
• Deontic About the way the world isnt now but
  needs to be.
• John must know French.
• Epistemic About our beliefs about the world.
• Seems to be a correlation between eventivity
  and modality type, in the adult language.

72
Modality and kids

• In other circles of research, people have
  proposed that kids basically dont have
  epistemic uses of modality (John must be a
  genius) before about 3 years oldfor whatever
  reason.
• If thats true, theres only deontic modality
  (John must go to class).
• If deontic modality only goes with eventive
  predicates, were done. Kids RIs are modal,
  necessarily deontic, hence necessarily with
  eventive verbs.

73
English must be different

• English bare forms are not (necessarily)
  infinitives, not necessarily modal, hence not
  necessarily deontic, eventive.
• Hence, the EC and MRE appear not to hold of
  English, but for reasons we can now understand.

74
A pause to regroup

• English bare form is unmarked, only -s is
  unambiguously TA.
• Do is a reflex of T (and/or A), and as
  expected, almost never in negative sentences was
  there a post-negation inflected verb (she doesnt
  go vs. she not goes).
• The actual infinitive morpheme in English is Ø,
  so we cant differentiate bare forms between
  infinitives and other bare forms.
• The infinitive morpheme seems to carry modal
  meaningin languages where you can see it you can
  tell. Effectively RI only with eventives.

75
A pause to regroup

• HH propose that the languages which show OIs are
  those which rely (only) on number in their
  inflectional system. Those that dont (Japanese
  tense only, Italian person) seem to be
  immune. Hence, person is the special, possibly
  omitted thing for kids.
• This isnt really distinctly at odds with ATOM.
  Wexler suggests that the problem is with
  double-movement of the subject, but movement of
  the subject might itself be driven by person
  features in recent versions of the syntactic thy.

76
A pause to regroup

• HH observed a correlation between specified
  (finite) subjects and verbal form.
• Specifically,finite subjects seem to cause
  finite verbs. Not obvious why this would be under
  ATOM directly, but it might be something like
  what HH suggestthere is feature sharing between
  the subject and the AgrP. It might be interesting
  to see if finite subjects necessarily always
  show the reflex of AgrP and not necessarily of TP.

77
Legendre et al. (2000)

• Wexler During OI stage, kids sometimes omit T,
  and sometimes omit Agr. Based on a choice of
  which to violate, the requirement to have T, to
  have Agr, to have only one.
• (cf. Kids in a pickle slide)
• Legendre et al. Looking at development (of
  French), it appears that the choice of what to
  omit is systematic we propose a system to
  account for (predict) the proportion of the time
  kids omit T, Agr, both, neither, in progressive
  stages of development.

78
Optimality Theory

• Legendre et al. (2000) is set in the Optimality
  Theory framework (often seen in phonology, less
  often seen applied to syntax).
• Grammar is a system of ranked and violable
  constraints

79
Optimality Theory

• In our analysis, one constraint is Parse-T, which
  says that tense must be realized in a clause. A
  structure without tense (where TP has been
  omitted, say) will violate this constraint.
• Another constraint is F (Dont have a
  functional category). A structure with TP will
  violate this constraint.

80
Optimality Theory

• Parse-T and F are in conflictit is impossible
  to satisfy both at the same time.
• When constraints conflict, the choice made (on a
  language-particular basis) of which constraint is
  considered to be more important (more highly
  ranked) determines which constraint is satisfied
  and which must be violated.

81
Optimality Theory

• So if F gtgt Parse-T, TP will be omitted.
• and if Parse-T gtgt F, TP will be included.

82
Optimality Theory

• Grammar involves constraints on the
  representations (e.g., SS, LF, PF, or perhaps a
  combined representation).
• The constraints exist in all languages.
• Where languages differ is in how important each
  constraint is with respect to each other
  constraint.

83
Optimality Theory big picture

• Universal Grammar is the constraints that
  languages must obey.
• Languages differ only in how those constraints
  are ranked relative to one another. (So,
  parameter ranking)
• The kids job is to re-rank constraints until
  they match the order which generated the input
  that s/he hears.

84
Legendre et al. (2000)

• Proposes a system to predict the proportions of
  the time kids choose the different options among
• Omit TP
• Omit AgrSP
• Omit both TP and AgrSP
• Include both TP and AgrSP (violating UCC)

85
French v. English

• English TAgr is pronounced like
• /s/ if we have features 3, sg, present
• /ed/ if we have the feature past
• /Ø/ otherwise
• French TAgr is pronounced like
• danser NRF
• a dansé (3sg) past
• je danse 1sg (present)
• jai dansé 1sg past

86
The idea

• Kids are subject to conflicting constraints
• Parse-T Include a projection for tense
• Parse-Agr Include a project for agreement
• F Dont complicate your tree with functional
  projections
• F2 Dont complicate your tree so much as to
  have two functional projections.

87
The idea

• Sometimes Parse-T beats out F, and then theres
  a TP. Or Parse-Agr beats out F, and then theres
  an AgrP. Or both Parse-T and Parse-Agr beat out
  F2, and so theres both a TP and an AgrP.
• But what does sometimes mean?

88
Floating constraints

• The innovation in Legendre et al. (2000) that
  gets us off the ground is the idea that as kids
  re-rank constraints, the position of the
  constraint in the hierarchy can get somewhat
  fuzzy, such that two positions can
  overlap. F Parse-T

89
Floating constraints

• F Parse-T
• When the kid evaluates a form in the constraint
  system, the position of Parse-T is fixed
  somewhere in the rangeand winds up sometimes
  outranking, and sometimes outranked by, F.

90
Floating constraints

• F Parse-T
• (Under certain assumptions) this predicts that we
  would see TP in the structure 50 of the time,
  and see structures without TP the other 50 of
  the time.

91
French kid data

• Looked at 3 French kids from CHILDES
• Broke development into stages based on a modified
  MLU-type measure based on how long most of their
  utterances were (2 words, more than 2 words) and
  how many of the utterances contain verbs.
• Looked at tense and agreement in each of the
  three stages represented in the data.

92
French kid data

• Kids start out using 3sg agreement and present
  tense for practically everything (correct or
  not).
• We took this to be a default
• (No agreement? Pronounce it as 3sg. No tense?
  pronounce it as present. Neither? Pronounce it as
  an infinitive.).

93
French kid data

• This means if a kid uses 3sg or present tense, we
  cant tell if they are really using 3sg (they
  might be) or if they are not using agreement at
  all and just pronouncing the default.
• So, we looked at non-present tense forms and
  non-3sg forms only to avoid the question of the
  defaults.

94
French kids data

• We found that tense and agreement develop
  differentlyspecifically, in the first stage we
  looked at, kids were using tense fine, but then
  in the next stage, they got worse as the
  agreement improved.
• Middle stage looks likecompetition between
  Tand Agr for a single node.

95
A detail about counting

• We counted non-3sg and non-present verbs.
• In order to see how close kids utterances were
  to adults utterances, we need to know how often
  adults use non-3sg and non-present, and then see
  how close the kids are to matching that level.
• So, adults use non-present tense around 31 of
  the timeso when a kid uses 31 non-present
  tense, we take that to be 100 success
• In the last stage we looked at, kids were
  basically right at the 100 success level for
  both tense and agreement.

96
Proportion of non-present and non-3sg verbs
97
Proportion of non-finite root forms
98
A model to predict the percentages

• Stage 3b (first stage)
• no agreement
• about 1/3 NRFs, 2/3 tensed forms F2 FParse
  T ParseA

99
A model to predict the percentages

• Stage 4b (second stage)
• non-3sg agreement and non-present tense each
  about 15 (about 40 agreeing, 50 tensed)
• about 20 NRFs F2 FParseT ParseA

100
A model to predict the percentages

• Stage 4c (third stage)
• everything appears to have tense and agreement
  (adult-like levels) F2 FParseT ParseA

101
Predicted vs. observedtense
102
Predicted vs. observedagrt
103
Predicted vs. observedNRFs
104
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