Associated Lattice-BERT for Spoken Language Understanding

Lattices are compact representations that can encode multiple speech recognition hypotheses in spoken language understanding tasks. Previous work has extended the pre-trained transformer to model lattice inputs and achieved significant improvements in natural language processing tasks. However, these models do not consider the global probability distribution of lattices path and the correlation among multiple speech recognition hypotheses. In this paper, we propose an associated Lattice-BERT, an extension of BERT that is tailored for spoken language understanding (SLU). Associated Lattice-BERT augments self-attention with positional relation representations and lattice scores to incorporate lattice structure. We further design a lattice confusion-aware attention mechanism in the prediction layer to push the model to learn from the association information between the lattice confusion paths, which mitigates the impact of the Automatic Speech Recognizer (ASR) errors on the model. We apply the proposed model to a spoken language understanding task, the experiments on the datasets of intention detection recognition show that our proposed method outperforms the strong baselines when evaluated on spoken inputs.