End-to-End Spoken Language Understanding with Tree-Constrained Pointer Generator
Guangzhi Sun, Chao Zhang, Philip C. Woodland
Abstract
End-to-end spoken language understanding (SLU) suffers from the long-tail word problem. This paper exploits contextual biasing, a technique to improve the speech recognition of rare words, in end-to-end SLU systems. Specifically, a tree-constrained pointer generator (TCPGen), a powerful and efficient biasing model component, is studied, which leverages a slot shortlist with corresponding entities to extract biasing lists. Meanwhile, to bias the SLU model output slot distribution, a slot probability biasing (SPB) mechanism is proposed to calculate a slot distribution from TCPGen. Experiments on the SLURP dataset showed consistent SLU-F1 improvements using TCPGen and SPB, especially on unseen entities. On a new split by holding out 5 slot types for the test, TCPGen with SPB achieved zero-shot learning with an SLU-F1 score over 50% compared to baselines which can not deal with it. In addition to slot filling, the intent classification accuracy was also improved.
BibTeX
@inproceedings{icassp2023_endtoendspokenla,
title = {End-to-End Spoken Language Understanding with Tree-Constrained Pointer Generator},
author = {Guangzhi Sun and Chao Zhang and Philip C. Woodland},
booktitle = {ICASSP 2023},
year = {2023}
}