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Developing a German grammar for analysis and generation using OpenCCG. Ciprian Gerstenberger University of Saarland IGK Colloquium January 13th 2005. Outline. NLP environments: a comparison The choice: OpenCCG The formalism: MMCCG The German grammar Future work. - PowerPoint PPT Presentation
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Developing a German grammar for analysis and generation using OpenCCG
Ciprian GerstenbergerUniversity of Saarland
IGK Colloquium January 13th 2005
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Outline
1. NLP environments: a comparison
2. The choice: OpenCCG
3. The formalism: MMCCG
4. The German grammar
5. Future work
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Dialogue systems
building dialogue systems → linguistic resources
linguistic resources → tools for developing and maintaining
wide range of different NLP environments
⇒ Which is the most appropriate environment for our purposes?
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NLP environments for dialogue systems
General requirements
both for analysis and generation multi-lingual easy domain reconfigurability
Requirements for NLG
realization of contextually sensitive utterances linguistically motivated control over flexible sentence realization
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NLP environments for dialogue systems
Technical requirements
freely available well documented offering support when needed freely available resources (for German) efficient platform independent
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NLP environments
KPML (Lisp): Systemic-Functional Grammar (SFG) OpenCCG (Java): Multi-Modal Combinatory Categorial Grammar
(MMCCG) Babel (Prolog): Head-Driven Phrase Structure Grammar (HPSG) LKB (Lisp): Head-Driven Phrase Structure Grammar (HPSG) XLE (C): Lexical Functional Grammar (LFG) XTAG (Lisp): Tree Adjoning Grammar (TAG) XDG (Oz): Topological Dependency Grammar (TDG)
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NLP environments: Babel
Babel-System (S. Müller)
implementing HPSG Prolog only analysis, no generation multi-lingual (?) resources for German: grammar with good coverage freely available documentation support (?)
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NLP environments: LKB
LKB
implementing HPSG Lisp multi-lingual both analysis and generation but: resources for German not usable for generation freely available documentation support (?)
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NLP environments: XTAG
XTAG
implementing TAG Lisp both analysis and generation multi-lingual resources for German (DFKI ?) freely available documentation support (?)
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NLP environments: XDG
XDG
implementing TDG Oz only analysis (generation as dependency parsing using TAGs) multi-lingual (?) resources for German (toy grammars) freely available documentation (?) support
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NLP environments: KPML
KOMET-Penman Multilingual Linguistic resource development
implementing Systemic-Functional Grammar (SFG) Lisp multi-lingual flexible generation good sentence realization control only for generation, no parsing resources for German: grammar with good coverage freely available documentation and support
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NLP environments: XLE
Xerox Linguistic Environment
implementing LFG C and Tcl/Tk multi-lingual both analysis and generation resources for German (not freely available) documentation support not freely available
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NLP environments: OpenCCG
OpenCCG
implementing Multi-Modal Combinatory Categorial Grammar (MMCCG)
open source Java-based NLP library both analysis and generation multi-lingual no resources for German, but grammars for English freely available documentation support
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NLP environments: The Choice
OpenCCG
Java-based NLP library → platform independent analysis and generation → uniform grammar resources multi-lingual → extendable used and in use in several other projects: FLIGHTS, COMIC, COSY supporting output format for TTS (e.g. APML) optimized sentence realization flexible generation sentence realization control
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Basic formalism: CCG
Combinatory Categorial Grammar
lexicalized grammar formalism
lexical items are assigned syntactic categories
combinatory rules
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MMCCG
Multi-Modal Combinatory Categorial Grammar
refining CCG by introducing means of controlling the application of combinatory rules
specifying modes on category forming operators (slashes)
making application of rules dependent on the slash mode
four basic modes governing different levels of associativity and permutativity
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Example
Der Hund sieht die Katze.
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Example (cont.)
Der Hund sieht die Katze.
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Developing a German Grammar
joint work with Magdalena Wolska (DIALOG Project)
Desiderata uniform resources for analysis and generation covering all phenomena in our domains achieve more generality of the grammar than wrt
phenomena encountered in our (relatively small) corpora
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Phenomena
Some phenomena in German
agreement position of the finite verb Topological Fields: controlling the Vorfeld complex sentences ambiguity controlling sentence realization
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Lexical forms
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Agreement
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Agreement (cont.)
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Agreement/Complex sentences
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Clause types
Verb-initial clauses
• yes/no questions:Soll ich die den Titel zu der Liste hinzufügen?
• alternative questions:Möchtest Du Mozart oder Bach hören?
imperatives:Wähle das Album „Californication“ von den Red Hot Chili Peppers!
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Clause types (cont.)
Verb-second clauses
main declarative: Der Titel wurde hinzugefügt.
• wh-question:Welcher Künstler spielt „Missunderstood“?
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Clause types (cont.)
Verb-final clauses
subordinate clause:Wenn Sie möchten, kann ich „We Just Can´t Get Enough CCG“ abspielen.
relative clause:Ich nehme aus den ersten vier Alben, die du hast, jeweils den ersten Song.
• complement clause:Ich glaube, daß das Album „Dangerously In Love“ heißt.
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Topological Fields
Controlling the Vorfeld occupation using flags
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Topological Fields (cont.)
Controlling the Vorfeld occupation using flags
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Analysis: Ambiguities
Der Hund von dem traurigen Mann den ich sah rennt.
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Analysis: Ambiguities (cont.)
Das Kind rennt wenn der Hund rennt weil die Katze rennt.
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Generation
Sentence realization without control
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Generation (cont.)
Sentence realization with control: fronted subject
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Generation (cont.)
Sentence realization with control: fronted object
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Future Work (1)
extending the grammar wrt the two domain currently modelled (MP3 and maths tutorial)
(AP, NP, sentence, etc.) coordination complex NP (e.g. postmodifications) control and raising verbs particle verbs (Ich spiele den Song ab vs. Ich möchte den
Song abspielen) Topological Fields: scrambling in the Mittelfeld
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Future Work (2)
analysis: coping with partial input, ill-formed utterances generation: realizing elliptical output using a dynamic morphological module development of an ontology