Applications and libraries/Linguistics

Portals and other huge resorces

Peter Ljunglöf's many publications on natural language processing, parsing, formal semantics. Many of them uses Haskell, and there are downloadable Haskell sources too.

Jan van Eijck's page contains a huge amount of materials on logic and language:

• computational linguistics
• logics (e.g. dynamic epistemic modelling)

There are many Haskell resources, too.

Natural language processors (and generators)

• Cypher is one of the first software program available which generates the metadata representation of natural language input. Cypher produces RDF graph and SeRQL query representations of sentences, clauses, phrases and questions. The Cypher framework provides a set of robust definition languages, which can be used to extend and create grammars and lexicons. Cypher programming is fun to learn and easy to use, and the specifications are designed to allow a novice to quickly and easily build transcoders for processing highly complex sentences and phrases of any natural language, and to cover any vocabulary
• GenI is a surface realiser for Tree Adjoining Grammars. Surface realisation can be seen as the last stage in a natural language generation pipeline. GenI in particular takes an FB-LTAG grammar and an input semantics (a conjunction of first order terms), and produces the set of sentences associated to the input semantics by the grammar.

Natural language processing and combinatory logic

Applicative universal grammar

Now it has got its own HaskellWiki page.

Categorial grammar

A general summary of modern semantic theories developed in the century is provided by Logical Aspects of Computational Linguistics: an introduction.

Gary Hardegree's portal-rich page provides a lot of materials on logic and linguistics, among them

• The Axiomatic Theory of Truth grasping concepts like truth, quotations, paradoxes, liar's paradox
• Courses ranging from the introductory level to developed topics, e.g. Basic Categorial Grammar.

The Combinatory Categorial Grammar Site contains links, papers (both introductory and developed) and software (OpenNLP open source projects, related to natural language processing, and OpenCCG)

On natural languages relating to combinatory logic, see also

• Peter Steedman's Does Grammar Make Use of Bound Variables?
• Mark Hepple: The Grammar and Processing of Order and Dependency: a Categorial Approach

Tree Adjoining Grammar

• See GenI, mentioned above.

Game theoretic semantics

Game theoretic semantics presents an interesting concept of truth -- in another way than that of Tarski. Its connections to computer science and computer languages is described in Wikipedia's Game semantics article. Merlijn Sevenster's Game theoretical semantics and -logic is a good introductory material too.

Chiaki Ohkura's The Semantics of Metaphor in the Game Theoretic Semantics with at Least Two Coordination Equilibria article tries to catch the concept of metaphor.

Relatedness to linear logic

The Wikipedia article mentions also the relatedness of game theoretic semantics to linear logic. Philip Wadler's page on linear logic describes the topic and its relatedness to many concepts concerning Haskell. A taste of linear logic can serve as an introductory article.

Parsing natural languages

Gordon J. Pace: Monadic Compositional Parsing with Context Using Maltese as a Case Study, see its context too.

Other functional or Haskell-related approaches to linguistics

• From Aarne Ranta's homepage
  • Grammatical Framework

  GF is a compiler and grammatical programming environment written entirely in Haskell, with an interactive interpreter and two GUI interfaces, one written in Fudgets and another written in Java. GF grammars are written in a subset of Haskell and compile into an internal GF format that may be used as embedded parsers in Haskell, parsers in Java (with an embedded Java interpreter gfc2java.jar) and subsequently converted to applets (Gramlets). (GF-Haskell to Java translation is performed through an Open Agent Architecture--the original .NET, see GF OAA.) The GF grammatical formalism handles linguistic entities (morphemes, etc.) using type theory: an approach especially suited to machine translation of controlled natural languages. The Grammar Resource Library, a set of basic grammars for Danish, English, Finnish, French, German, Italian, Norwegian, Russian, Spanish and Swedish, is available as a separate download. GF has been used to translate a fragment of C code to JVM (see GFCC (PDF document)).

  • Natural Language Technology, with (among others) online course slides. They give huge insights, for example, see the slide example which discusses the concept of dependent type and Curry Howard isomorphism in lingustical context.
• Functional Morphology
• The Zen Computational Linguistics Toolkit has tools for efficiently processing linguistic data structures, like trees and automata. It's written in Literal O'Caml, though a Haskell port shouldn't be very hard to do.
• The natural language processing blog written by Hal Daume III.

Other linguistics-related resources

Dr. Günter Neumann's homepage.

Lojban, an artificial language. (see also Wikipedia on it.) “Lojban was not designed primarily to be an international language, however, but rather as a linguistic tool for studying and understanding language. Its linguistic and computer applications make Lojban unique among international languages...” (NC:WhLoj, page 15 par 1)

References

NC:WhLoj

Nicholas, Nick and Cowan, John (ed.): What is Lojban? Logical Language Group, 2003. Available also online.