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

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GRS LX 700Language Acquisition andLinguistic
Theory

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

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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?

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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

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.
• Patoshik wanted PRO to go to Holland.
• 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, recall (truncation)
• 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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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.

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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.

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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.

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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.

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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
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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.

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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.

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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.

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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.

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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.

46
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.

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Root infinitives vs. time

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

48
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?

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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.

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CHILDES

• Child Language Data Exchange Systemhttp//childes
  .psy.cmu/edu
• Founded in 1984, Concord, MA.Director Brian
  MacWhinney macw_at_mac.com.
• A source of, among other things,
  computerizedsearchabletranscripts of child
  speech.
• Note When using data from CHILDES, you must
  always cite the original source of the data. See
  the CHILDES database manual for details on what
  to cite for each corpus.

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Components

• CHAT Chat is a transcription protocol common to
  most transcripts in the CHILDES database.
• CLAN CLAN is a program (actually a collection of
  programs) used to transcribe data and analyze
  transcripts.
• CHILDES The database itself consists of the
  transcripts (or other data, e.g., video, audio).

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CHAT
_at_UTF8 _at_Begin _at_Languages en _at_Participants CHI
Peter Target_Child, MOT Mother, LOI Lois
Investigator, PAT Patsy Investigator, LYN Lynn
Investigator, JEN Jennifer Child _at_ID enbloom70
CHI21.malenormalTarget_Child _at_ID enbloom
70MOTMother _at_ID enbloom70LOIInvest
igator _at_ID enbloom70PATInvestigator _at_I
D enbloom70LYNInvestigator _at_ID enbloom
70JENChild _at_Tape Location Tape 16, side
1 _at_Comment MLU 2.39 _at_Time Start 1500 _at_Situation
Peter is just waking up from nap when Lois and
Patsy arrive, adults talk about Jennifer who is
now five and a half months old PAT hey Pete
that's a nice new telephone looks like it must
do everything it must ring and talk and
. mor cohey npropPete prodemthatvbe3S
deta adjnice adjnew ntelephone nlook-PL
vlike proit vauxmust vdo proindefeverything
proit vauxmust vring conjcooand ntalk
conjcooand . exp Peter has a new toy
telephone on table next to him com ltbefgt
untranscribed adult conversation CHI xxx
telephone go right there . mor unkxxx
ntelephone vgo advright advlocthere .
act ltbefgt reaches out to lift phone receiver,
pointing to place where wire should connect
receiver and telephone MOT the wire
. mor detthe nwire .

• The CHAT format guidelines for coding your own
  transcripts are quite involved
• see the extensive manual for details.
• headers
• _at_Participants
• speaker tiers
• CHI, PAT
• unintelligible speech
• xxx, ignored.
• xx, a word.

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CLAN

• Analysis programs and transcript/text editor.
• Directories
• working where it looks for transcript files to
  analyze
• output where it will put output files, default
  is working directory
• lib and mor lib where it looks for its own
  files, should be leave-able-as-is. If in doubt,
  set to lib in the same folder as the program file.

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CLAN

• CLAN button pops up command list.
• FILE IN choose file(s) to analyze.
• Recall get back previous command.
• Command window where the real action is. We
  dont need no stinkin buttons.
• Run perform the action you asked for in the
  Command window.

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CLAN

• Useful commands
• freq calculate frequency of words in
  transcript(s)(page 71).
• combo search for things in the transcripts(page
  56).
• mlu calculate mean length of utterance in the
  transcripts(page 94).

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mlu
LOI why don't you bring your telephone down
here Peter ? mor advwhwhy vauxdonegnot
proyou vbring propossdetyour ntelephone
advdown advlochere npropPeter ? LOI why
don't you put it on the floor ? mor advwhwhy
vauxdonegnot proyou vputZERO proit
prepon detthe nfloor ? act ltaftgt Peter
puts it on floor ltaftgt Peter is trying to attack
"wire" to phone and receiver com ltaftgt
untranscribed adult conversation LOI what're
you doing ? mor prowhwhatvbePRES proyou
partdo-PROG ? CHI 0 . act ltaftgt Peter goes
to hall closet, tries to open it MOT what do
you need ? mor prowhwhat vdo proyou vneed
? CHI xxx . mor unkxxx . MOT no don't
see ? mor cono vauxdonegnot vsee ?
gpx pointing to hook which locks closet door
out of Peter's reach com ltaftgt untranscribed
adult conversation CHI xxx . mor unkxxx .
act ltbefgt goes to his room looking for
toys MOT well they brought something too
. mor cowell prothey vbringPAST
proindefsomething advtoo . act ltbefgt sends
him back PAT shall we take the ark
? mor vauxshall prowe vtake detthe nark ?
act ltaftgt goes to Peter's room, suggests they
bring some of Peter's toys to living room

• The mlu command computes the mean length of
  utterance in morphemes. Used as a rough measure
  of the childs linguistic development.
• Requires that CLAN can tell what the morphemes
  are.
• Many transcripts are tagged with mor tiers for
  this purpose. Morphemes are delimited by, e.g,.
  -, , and (see CHAT manual)
• whatreprowhwhatvbePRES
• broughtvbringPAST

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freq
gt freq sample.cha freq sample.cha Sun Sep 12
194856 2004 freq (10-Sep-2004) is conducting
analyses on ALL speaker tiers
From file ltsample.chagt
1 a 1 any 1 are 3 chalk 1 chalkchalk 1
delicious 1 don't 1 eat . . . 1 toys
2 toys 3 want 1 what 2 what's 1
wonderful 2 yeah 2 you -----------------------
------- 34 Total number of different word
types used 50 Total number of words
(tokens) 0.680 Type/Token ratio

• The freq command tallies up the number of times
  each word appears in the transcript.
• Useful to figure out which words are most common
  (or which words are used at all) in a childs
  transcript.

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combo

• The combo command is used to search for patterns
  in the transcripts.
• For all of the commands (including freq and mlu),
  there are certain options you should specify
• Tier tCHI
• Input file(s) nina
• Output file gt outfile.txt
• For example
• freq tCHI nina10.cha gt freq-nina10.txt
• mlu tCHI nina gt mlu-nina.txt

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combo options

• In addition to those, combo has a couple of other
  options we care about
• s"eat" search forpattern in ""
• s_at_fname search forpatterns in fname
• w2 show 2 lines after a found result
• -w2 show 2 lines before a found result
• For example
• combo w2 -w2 s"eat" nina10.cha gt eatn10.txt

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Searches with combo

• xyfinds x immediately followed by y (full
  words)
• finds anything
• xyfinds x or y
• !xfinds anything but x
• _finds any one character

• xyfinds x eventually followed by y
• ingfinds anything ending in ing
• the!grey(dogcat)finds the followed
  eventually by something other than grey, followed
  eventually by either dog or cat. Finds the black
  cat, the big red dog, but not the grey cat
  (though why?)

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Fabulous now what does this have to do with root
infinitives?

• Harkening back, we talked about a couple of ideas
  about whats wrong with kids trees.
• Each idea makes predictions about what kids will
  and wont sayand CHILDES can be used to see to
  what extent these predictions are met.
• Relatively painless computerized searching
• relative to pen and paper, at least
• A lot of data available, a lot of kids available

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