James Ryan

Stephanie M. Lukin, James O. Ryan, Marilyn A. Walker

Dialogue authoring in large games requires not only content creation but the subtlety of its delivery, which can vary from character to character. Manually authoring this dialogue can be tedious, time-consuming, or even altogether infeasible. This paper utilizes a rich narrative representation for modeling dialogue and an expressive natural language generation engine for realizing it, and expands upon a translation tool that bridges the two. We add functionality to the translator to allow direct speech to be modeled by the narrative representation, whereas the original translator supports only narratives told by a third person narrator. We show that we can perform character substitution in dialogues. We implement and evaluate a potential application to dialogue implementation: generating dialogue for games with big, dynamic, or procedurally-generated open worlds. We present a pilot study on human perceptions of the personalities of characters using direct speech, assuming unknown personality types at the time of authoring.

Adam James Summerville, James Ryan, Michael Mateas et al.

In this paper, we present a novel approach to natural language understanding that utilizes context-free grammars (CFGs) in conjunction with sequence-to-sequence (seq2seq) deep learning. Specifically, we take a CFG authored to generate dialogue for our target application for NLU, a videogame, and train a long short-term memory (LSTM) recurrent neural network (RNN) to map the surface utterances that it produces to traces of the grammatical expansions that yielded them. Critically, this CFG was authored using a tool we have developed that supports arbitrary annotation of the nonterminal symbols in the grammar. Because we already annotated the symbols in this grammar for the semantic and pragmatic considerations that our game's dialogue manager operates over, we can use the grammatical trace associated with any surface utterance to infer such information. During gameplay, we translate player utterances into grammatical traces (using our RNN), collect the mark-up attributed to the symbols included in that trace, and pass this information to the dialogue manager, which updates the conversation state accordingly. From an offline evaluation task, we demonstrate that our trained RNN translates surface utterances to grammatical traces with great accuracy. To our knowledge, this is the first usage of seq2seq learning for conversational agents (our game's characters) who explicitly reason over semantic and pragmatic considerations.