ExpReal: A Writing Language and System for Authoring Texts in Interactive Narrative

ExpReal functions as a surface realizer and templating language designed to bridge the gap between generic natural language generation and manual, canned text authoring in interactive narratives. The system enables authors to create flexible, expressive dialogue templates that automatically adapt to dynamic game states, such as character emotions or specific narrative tasks. By utilizing a two-step process—variable resolution followed by surface realization—the system ensures that generated text remains grammatically correct and contextually appropriate while maintaining the author’s stylistic intent.

The system addresses the core conflict between genericity, which requires abstract structures to cover many scenarios, and authorability, which demands precise, colorful language. ExpReal allows authors to define templates in simple spreadsheet formats, supporting English, French, and Dutch. These templates incorporate grammatical blocks for features like pronominalization, inflection, and ownership, which are processed using the SimpleNLG-NL engine. The system also supports conditional logic, allowing for variable specificity where templates are selected based on the current world state, thereby ensuring high variability and preventing repetitive, mechanical dialogue.

ExpReal has been successfully implemented in two distinct applications: the Alzheimer Care Trainer, a 3D simulation for caregiver training, and Feline, an interactive narrative testbed. These use cases demonstrate the system's ability to handle complex, personalized dialogue in real-time. By providing an open-source, accessible framework that does not require deep programming expertise, the system offers a practical solution for developers seeking to enhance the quality and responsiveness of character interactions in interactive media. Future development aims to further refine the syntax to improve readability for non-technical authors and provide real-time output previews during the writing process.