In an earlier blog post we wrote about the need for dynamic text generation in the Alzheimer Care Trainer (ACT): because the simulation changes all the time depending on the caregiver’s interactions with the virtual character and the virtual environment, it’s simply not doable to write all the sentences used in the simulation by hand; especially not for all three languages ACT is available in. The solution we developed for this within POSTHCARD is the authoring and text generation tool ExpReal, of which we discussed the basic mechanism in another blog post.

In September we had the opportunity to present ExpReal to a multidisciplinary audience of researchers at the international conference on Foundations of Digital Games (FDG 2020). In the paper published in the FDG conference proceedings [1], we argue that tools for text generation in interactive narratives (such as games) must meet the following requirements:

  • Author ability: authors should be able to write their own texts with the tool and annotate them in such a way that variations of the text can be automatically generated.
  • Variability: the tool must make it possible to express the same thing in different ways.
  • Correctness: obviously, the sentences that are generated by the tool need to be correct and appropriate in style.
  • Variable levels of specificity: the tool should make it possible to have texts at different levels of specificity: generic texts, which are applicable in all kinds of situations, and more specific ones, which can be used only in specific situations.

A Writing Language and System for Authoring Texts in Interactive Narrative

ExpReal was designed to meet all of these requirements. In the rest of the paper we describe the technical details of ExpReal, illustrated with examples of its use in ACT and another narrative simulation system.

In the paper, we also compare ExpReal to other authoring tools for text generation in interactive narratives. The main properties that make ExpReal different from other tools are (1) its use of templates in combination with a language generation system called SimpleNLG, and (2) its multilinguality: unlike other systems, which tend to be for English only, ExpReal currently works in three languages (English, French and Dutch) and is extendable to other languages with moderate effort.

[1] Nicolas Szilas, Ruud de Jong and Mariët Theune (2020). ExpReal: a Writing Language and System for Authoring Texts in Interactive Narrative. Proceedings of Foundations of Digital Games 2020 (FDG2020), Article No.: 12.