Program for Language Analysis and Inference


University of Heidelberg, Department of Computational Linguistics, Copyright Peter Hellwig & Heinz-Detlev Koch



Versatile Tool for Grammar Writing

Useful for Teaching, Research and Development, and real NLP Applications


PLAIN is a Natural Language Processing system. At the same time it is an Integrated Development Environment for (computational) linguists. It offers many tools for testing and debugging while the linguist is drawing up a Dependency Unification Grammar (DUG). The formalism of DUG is Dependency Representation Language (DRL). Since PLAIN is an interpreter of DRL, DRL is so to speak a high level programming language for linguists


PLAIN qualifies especially for start-up projects that try to extent language processing to languages lacking resources so far. DRL is simple and perspicuous. A DRL expression consists of a dependency tree structure and sets of attribute and values. It should be possible to create appropriate attributes for most predicates that empirical linguists use when describing languages informally. Therefore it is easy to "translate" printed dictionaries and school grammars into DRL. Nevertheless the implementation is very efficient.


PLAIN offers the following functionality:




-          Morphological paradigms derived from cardinal forms (i.e. item and process morphology).

-          Paradigms executed as FTN (i.e. item and arrangement morphology).




-          Lexicalistic approach to syntax, "every word behaves differently".

-          A template is drawn up for each particular syntagmatic relation.

-          Syntactic frames are associated with lexemes in terms of templates.

-          Slot and filler chart parsing.

-          "Customized" unification; attributes together with templates function as "word experts".

-          Covering complements and adjuncts, nucleus and raising, compounds, discontinuous constituents, coordination, ellipsis and much more.


Tagger based on full or partial parsing


-          Unlimited range of tags (attributes and values) among which syntagmatic roles and semantic features.




-          Paraphrasing, translation, inferring.


Surface Generator


-          Creating natural language phrases from DRL representations.










is available


for free




(for non-commercial use)





First Steps with PLAIN

The User's Guide to PLAIN

The Linguist's Guide to PLAIN: 1 Morphology

The Linguist's Guide to PLAIN: 2 Syntax

PLAIN Technical Guide

Background: Dependency Unification Grammar




Try it out and give us feed back!




Get a copy of PLAIN Version 2.0 with demonstration lingware here!