2. THE BIG PICTURE

3. Basic Assumptions Linguistics is the empirical science that studies language (or linguistic behavior) Linguistics proposes theories (models) that can be verified or falsified against linguistic data Computational linguistics is the branch of linguistics that uses computational models Natural language processing (NLP) is the engineering equivalent of computational linguistics (as civil engineering is to physics)

4. The Big Picture Empirical Matter Formalisms Data structures Formalisms Algorithms Distributional Models Maud expects there to be a riot *Teri promised there to be a riot Maud expects the shit to hit the fan *Teri promised the shit to hit the Linguistic Theory ? ? ? ?

5. Empirical Matter: Language and/or Linguistic Behavior Grammaticality Judgments Corpora Psycholinguistic Experiments Brain Scans Maud expects there to be a riot *Teri promised there to be a riot Maud expects the shit to hit the fan *Teri promised the shit to hit the fan

6. Empirical Matter: Language and/or Linguistic Behavior Grammaticality Judgments Corpora Psycholinguistic Experiments Brain Scans Maud expects there to be a riot *Teri promised there to be a riot Maud expects the shit to hit the fan *Teri promised the shit to hit the fan (?)

7. Underlying Empirical Object of Study What is linguistics really “about”? o The brain (cognitive science) o Language as an abstract structure (structuralism)

8. The Big Picture Empirical Matter Formalisms Data structures Formalisms Algorithms Distributional Models Maud expects there to be a riot *Teri promised there to be a riot Maud expects the shit to hit the fan *Teri promised the shit to hit the Linguistic Theory ? ? ? or

9. Mathematical Formalisms (1) Data Structures Phrase-structure trees Dependency trees Dags … Formalisms CFG TAG Dependency grammars Unification grammars … Algorithms Chart parsing Bottom-up Top-down … Deterministic parsing LR … Generation … Distributional Models Probabilistic CFG Probabilistic TAG …

10. Mathematical Formalisms (2) Exist in formal computer science, mathematics, statistics… Exist independently of natural language Do not on their own attempt to model or explain natural language Do not on their own succeed in modeling or explaining natural language

11. The Big Picture Empirical Matter Formalisms Data structures Formalisms Algorithms Distributional Models Maud expects there to be a riot *Teri promised there to be a riot Maud expects the shit to hit the fan *Teri promised the shit to hit the Linguistic Theory ? ? or

12. Linguistic Theory Phonetics: articulated sounds Phonology: how do sounds form minimal meaning units (morphemes)? Morphology: how do morphemes form words? Syntax: how do words form utterances? Semantics: what is the meaning of utterances? Pragmatics: in what context do we use which utterance?

13. Goal of Syntactic Theory (1) Goal (version 1): formulate theory of how words form utterances (sentences, in written language) Goal (version 2): formulate theory of how words in linear sequence combine to form utterances Utterance represented by non-linear structure (e.g., a tree)

14. Goal of Syntactic Theory (2) Goal (version 3): formulate theory of how words in linear sequence correspond to structures Assumption: semantics interprets this structure as meaning -- in particular, predicate-argument structure Goal (version 4): formulate theory of how words in linear sequence correspond to predicate-argument structures

15. Goal of Syntactic Theory (3) What is predicate-argument structure? seem like applesJohn John seems to like apples Deep dependency-like structure!

16. Goal of Syntactic Theory (4) So what role does phrase-structure play? “Augmented” representation of linear order S S Vi NP V V John seems likeapples t

17. Goal of Syntactic Theory (5) Goal (version 5, final for us): formulate theory of how phrase structure of sentences relates to their deep dependency Goal (version 5 – dependency theories): formulate theory of how surface dependency of sentences relates to their deep dependency

18. The Big Picture Empirical Matter Formalisms Data structures Formalisms Algorithms Distributional Models Maud expects there to be a riot *Teri promised there to be a riot Maud expects the shit to hit the fan *Teri promised the shit to hit the or Linguistic Theory ? theory of

19. Components of a Syntactic Theory (1) Definition of surface representation o Choice of data structure/formalism/… o List of node labels, rules, etc. Definition of deep representation o Choice of data structure/formalism/… o List of node labels, rules, etc. Description of correspondence o Choice of formal mechanism o List of rules (?)

20. Components of a Syntactic Theory (2) Formal Framework o Definition of surface representation  Choice of data structure/formalism/… o Definition of deep representation  Choice of data structure/formalism/… o Description of correspondence  Choice of formal mechanism Linguistic Content o Definition of surface representation  List of node labels, rules, etc. o Definition of deep representation  List of node labels, rules, etc. o Description of correspondence  List of rules (?)

21. The Big Picture Empirical Matter Formalisms Data structures Formalisms Algorithms Distributional Models Maud expects there to be a riot *Teri promised there to be a riot Maud expects the shit to hit the fan *Teri promised the shit to hit the or Linguistic Theory Content Surface representation (eg, ps) Deep representation (eg, dep) Correspondence uses theory of

22. Note on Competence vs Performance Performance: human sentence processing o Language use o Interacts with other parts of cognition: memory, emotions, etc o Studied in psychology, data from experiments Competence: human knowledge of syntax that allows performance o What we have been and will be talking about in this course, largely o Studied in linguistics, data from grammaticality judgments and corpora Distinction debatable

23. Content of a Syntactic Theory (1) Defeasible predictive theory: o Have theory o Needs to be able to make predictions (=deductions) o Predictions need to be verifiable or falsifiable against empirical matter o When prediction is falsified, theory needs to be changed  Formal framework  And/or linguistic content “Hypothetico-deductive method” (Popper)

24. Content of a Syntactic Theory (2) What exactly is being predicted? o Set of allowable surface representations:  Is predicted sentence in the language? o AND correspondence between surface representation and deep representation:  Is the predicted correspondence plausible? What is scope of theory? o One language: descriptive theory o All languages: explanatory theory (Chomsky)

25. Descriptive Theory Theory for one language, which is fixed Predicts what surface structures (i.e., strings) are grammatical Predicts, for a given grammatical string (and its surface representation) its deep representation

26. Explanatory Theory (1) Need to predict, given a language, what its surface structures and corresponding deep structures are Need a parameterized theory Chomsky (1981, etc): o Principles: things that hold for all languages o Parameters: values differ for different languages “Principles-and-paremeters” type theory also used by other researchers (TAG, HPSG, LFG)

27. Explanatory Theory (2) FormalismLinguistic Content Principles CFG with slash categories Head percolation algorithm … Set of nonterminal symbols Some rules for head percolation algorithm … Parameters Number of slashes allowed per nonterminal … Whether or not VP is used is standard declarative clause Rules of CFG … Example

28. Linguistic Theories and Empiricial Matter What is predicted? How can the theory be falsified? o Behavior of observable data What is the theory “about”? o Descriptive theory: language as structure o Explanatory theory: presumably, cognition

29. The Big Picture Final, for now Empirical Matter Formalisms Data structures Formalisms Algorithms Distributional Models Maud expects there to be a riot *Teri promised there to be a riot Maud expects the shit to hit the fan *Teri promised the shit to hit the or Linguistic Theory Content Surface representation (eg, ps) Deep representation (eg, dep) Correspondence uses descriptive theory is about explanatory theory is about predicts

30. The Big Picture Final, for now Empirical Matter Formalisms Data structures Formalisms Algorithms Distributional Models Maud expects there to be a riot *Teri promised there to be a riot Maud expects the shit to hit the fan *Teri promised the shit to hit the or Linguistic Theory Content Surface representation (eg, ps) Deep representation (eg, dep) Correspondence uses descriptive theory is about explanatory theory is about predicts In course so far

31. The Big Picture Final, for now Empirical Matter Formalisms Data structures Formalisms Algorithms Distributional Models Maud expects there to be a riot *Teri promised there to be a riot Maud expects the shit to hit the fan *Teri promised the shit to hit the or Linguistic Theory Content Surface representation (eg, ps) Deep representation (eg, dep) Correspondence uses descriptive theory is about explanatory theory is about predicts In rest of course