End-to-End Spoken Language Understanding for Generalized Voice Assistants
This work addresses the challenge of handling diverse intents and arguments in commercial voice assistants, representing an incremental advancement over previous domain-specific approaches.
The paper tackles the problem of developing an end-to-end spoken language understanding system for generalized voice assistants, achieving a 43% improvement in accuracy on a complex internal dataset and a nearly 20% improvement on a hard test set with unseen slot arguments.
End-to-end (E2E) spoken language understanding (SLU) systems predict utterance semantics directly from speech using a single model. Previous work in this area has focused on targeted tasks in fixed domains, where the output semantic structure is assumed a priori and the input speech is of limited complexity. In this work we present our approach to developing an E2E model for generalized SLU in commercial voice assistants (VAs). We propose a fully differentiable, transformer-based, hierarchical system that can be pretrained at both the ASR and NLU levels. This is then fine-tuned on both transcription and semantic classification losses to handle a diverse set of intent and argument combinations. This leads to an SLU system that achieves significant improvements over baselines on a complex internal generalized VA dataset with a 43% improvement in accuracy, while still meeting the 99% accuracy benchmark on the popular Fluent Speech Commands dataset. We further evaluate our model on a hard test set, exclusively containing slot arguments unseen in training, and demonstrate a nearly 20% improvement, showing the efficacy of our approach in truly demanding VA scenarios.