Practical Generation of Natural Language Text

Logo: TG/2

Dynamically generated text is necessary for many intelligent applications that provide information or include a need to communicate. Many of these applications - for instance, stock market reports, wheather reports, appointment scheduling dialogues - are characterized by stereotypical formulations instantiating only a limited set of parameters. For instance, in appointment scheduling negotiations, suggestion, acceptance, rejection or counter-suggestion of a date are the basic speech acts. For environmental air quality reports, condensed descriptions of time series and of exceeding threshold values are most important.

These applications allow for a complete a-priori structuring of the texts to be generated, which renders it possible to dispense with complex text planning and inference tasks that usually form a prerequisite for generating high-quality, readable text. It is perfectly adequate to address the problem with a more handsome approach.

It is for this kind of application that TG/2 offers a commercially viable solution. TG/2 can deal with different kinds of input representations.. Flat input, such as a list of domain-specific attribute-value pairs, can be accomodated as well as complex structured logical form representations of sentential semantics.

TG/2 stands for a flexible generation of template-based generators. The system is organized as a classical production system, separating the generation rules from their interpreter. Generation rules are defined as condition-action pairs. They can represent not only templates but also context-free grammar rules, using category symbols. Integrating these rule types into a single formalism allows for a shallow modelling of language where this proves sufficient, or for more fine-grained models whenever necessary. The interpreter consists of the standard three-step processing cycle:

By simultaneously designing rule systems for multiple languages, one gets multilingual generation almost for free. Developing a rule system for an additional language costs much less effort than the initial system since associations to input structures can be copied in most cases.

TG/2 is implemented in Allegro Common Lisp and runs on Unix and PC platforms.

Project Manager:Stephan Busemann (Stephan.Busemann@dfki.de)
Contact:Stephan Busemann (Stephan.Busemann@dfki.de)