Day 2: LFG approaches to information structure LFG The nature of - PowerPoint PPT Presentation

Day 2: LFG approaches to information structure LFG – The nature of f-structure An f-structure is restricted by the principles of • LFG in a nutshell • completeness : a predicate and all its arguments be a part of the structure • Grammaticized discourse functions in the f-structure • coherence : all arguments in the structure must be required by a predicate – Introducing the idea (Bresnan and Mchombo 1987) – Linking discourse functions to phrase structure positions • uniqueness : every attribute has a single value (King 1995; Butt and King 1996) – Problems with discourse features as part of the f-structure (King 1997) • Information structure as an independent projection – Introducing the idea (King 1997; Butt and King 2000) – new and prom as discourse features (Choi 1999) 1/39 3/39 LFG in a nutshell LFG – How a string is licensed LFG distinguishes two distinct representations: • A context-free c-structure grammar licenses the c-structure of a string. • c-structure (constituent structure): • The grammar is augmented with functional descriptions, which map the overt linear and hierarchical organization of words into phrases c-structure to an f-structure representation. • f-structure (functional structure): abstract functional organization of the sentence, explicitly representing syntactic predicate-argument structure and functional relations 2/39 4/39

An example grammar I: The c-structure rules with annotations A sentence licensed by the example grammar (based on Kaplan and Bresnan 1995) f 1 :S ( ↑ subj)= ↓ ↑ = ↓ (1) a. S → NP VP f 2 :NP f 3 :VP ( ↑ subj) = ↓ ↑ = ↓ ( ↑ spec)=a ( ↑ n)=sg ( ↑ tense)=past ( ↑ obj)= ↓ ( ↑ num)=sg ( ↑ pred)= ‘girl’ b. NP → Det N ( ↑ pred)= ‘hand < ... > ’ f 4 :NP Det N ↑ = ↓ ↑ = ↓ V A girl handed c. VP → V NP NP ( ↑ det)=the ( ↑ num)=sg ( ↑ obj2)= ↓ ( ↑ obj) = ↓ ( ↑ obj2) = ↓ Det ( ↑ pred)= ‘baby’ f 5 :NP N the baby ( ↑ spec)=a ( ↑ num)=sg ( ↑ num)=sg ( ↑ pred)= ‘toy’ Det N 5/39 a toy An example grammar II: The lexicon The f-structure resulting for the example sentence 2 2 3 3 spec a (2) a. a ( ↑ spec ) = a Det subj f 2 : num sg 6 6 7 7 ( ↑ num ) = sg 6 4 5 7 6 7 pred ’girl’ 6 7 6 7 tense past 6 7 b. girl ( ↑ num ) = sg N 6 7 pred ‘hand < ( ↑ subj), ( ↑ obj), ( ↑ obj2) > ’ 6 7 ( ↑ pred ) = ’girl’ 6 7 2 3 6 7 f 1 , f 3 : spec the 6 7 6 7 obj f 4 : num sg 6 7 c. ( ↑ tense ) = past handed V 6 7 4 5 6 7 pred ‘baby’ 6 7 ( ↑ pred ) = ’hand < ( ↑ subj ), ( ↑ obj ), ( ↑ obj2 ) > ’ 6 7 6 2 3 7 spec a 6 7 6 7 d. ( ↑ spec ) = the the Det obj2 f 5 : num sg 6 7 6 7 4 5 4 5 pred ‘toy’ e. baby N ( ↑ num ) = sg ( ↑ pred ) = ’baby’ f. toy ( ↑ num ) = sg N ( ↑ pred ) = ’toy’ 6/39 8/39

Grammaticized discourse functions in the f-structure The syntactic role of TOPIC and FOCUS Bresnan and Mchombo (1987): Bresnan and Mchombo (1987) adopt three principles about the role of the topic and focus functions in the grammars of natural language: • Grammatical functions are partitioned into – argument functions ( subj, obj, obl, . . . ) 1. In relative clauses, the relative pronoun or relativized constituent universally – non-argument functions ( topic, focus, adjunct, . . . ) bears the topic function. • Argument functions are directly mapped onto semantic or thematic roles in (3) The car [which you don’t want ] is a Renault. lexical predicate-argument structures. topic obj • Non-argument functions must be linked to other grammatical functions by the 2. In interrogative clauses, the interrogative pronoun or questioned constituent Extended Coherence Condition : universally bears the focus function. – All functions in the f-structure must be bound . (4) I know [what you want ]. – An argument function is bound if it is the argument of a predicator ( pred ). focus obj – A topic or focus is bound whenever it is functionally identified with, or anaphorically binds, a bound function. 9/39 11/39 The discourse functions of topic and focus The syntactic role of TOPIC and FOCUS (cont.) 3. The same constituent cannot be both focus and topic of the same level of • The topic designates what is under discussion, whether previously mentioned (functional) clause structure. of assumed in discourse (cf., Chafe 1976). Grammaticized topics – constituents that bear the topic function – designate (5) [It is my car [that you don’t want ]]. discourse topics; but not all discourse topics are grammatically marked. focus topic obj In cleft constructions, the same phrase is interpreted as both a focus and a • A focus expresses contrast in the sense of Chafe (1976); it designates topic, but at different levels of embedding. something that is not presupposed (relative to some context). Again, not all discourse foci are grammatically marked. The three principles should ultimately derive form the theory of the role and interpretation of these functions in discourse. Until there are more explicit theories of the interpretations of these functions in discourse, Bresnan and Mchombo (1987) postulate the above properties of the grammaticized discourse functions in order to derive explicit predictions. 10/39 12/39

Linking discourse functions to phrase structure positions Illustrating the analysis of Bresnan and Mchombo (1987) The empirical issue: • King (1995) examines word order and the encoding of topic and focus in Russian. In English, it is possible to embed a cleft construction in a question and question the clefted NP as in (6a) and (6b). • She argues that certain phrase structure positions license discourse functions. (6) a. (Mary asked) what it was that Fred cooked. • Annotations on the c-structure are used for the syntactic encoding of discourse b. (I asked) who it was that Marilyn suspected. functions, mapping a constituent to a grammatical and a discourse function. It is less acceptable to embed the cleft construction in a relative clause where the clefted NP functions as the relative pronoun as in (7a) and (7b), (7) a. ?? (Mary ate) what it was that Fred cooked. b. ?? (I met) the person who it was that Marilyn suspected. 13/39 15/39 Bresnan and Mchombo’s information structure explanation An example for the approach of King (1995) The cleft NP and the question phrase in the first example set both have foc The c-structure rule in (10) captures that in Russian li -questions the constituent functions, so that none of the principles for discourse functions are violated: preceding the li is the focus of the yes-no question. (8) a. [it was who [that Marilyn suspected ]] (10) CP → XP C’ focus topic obj ↓ = ( ↑ q-foc) ↑ = ↓ ( ↑ xcomp*gf)= ↓ b. [who it was [that Marilyn suspected ]] focus focus topic obj 2 3 pred ‘read < subj , obj > ’ (11) Knigu li ty proˇ citala? h i 6 7 q-foc book Q you read 6 7 The relative clauses in the second example set violates the principle that the 6 7 h i 6 7 subj pred ‘you’ same constituent cannot be both focus and topic of the same level of clause ‘Was it a book that you read?’ 6 7 6 7 h i structure (trace of the cleft NP is foc ; relativized cleft NP is top ) 4 5 obj pred ‘book’ (9) a. [it was who [that Marilyn suspected ]] focus topic obj b. [the person [who it was [that Marilyn suspected ]] topic focus topic obj 14/39 16/39