An Empirical Study of Transformer-Based Neural Language Model Adaptation

• Published in: ICASSP 2020 - 2020 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) pp. 7934 - 7938
• Main Authors: Li, Ke, Liu, Zhe, He, Tianxing, Huang, Hongzhao, Peng, Fuchun, Povey, Daniel, Khudanpur, Sanjeev
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.05.2020
• Subjects: Adaptation models; automatic speech recognition; Data models; Interpolation; language model adaptation; linear interpolation; Merging; Mixers; neural language model; Speech processing; Switches; Transformer
• ISSN: 2379-190X
• DOI: 10.1109/ICASSP40776.2020.9053399

We explore two adaptation approaches of deep Transformer based neural language models (LMs) for automatic speech recognition. The first approach is a pretrain-finetune framework, where we first pretrain a Transformer LM on a large-scale text corpus from scratch and then adapt it to relatively small target domains via finetuning. The second approach is a mixer of dynamically weighted models that are separately trained on source and target domains, aiming to improve simple linear interpolation with dynamic weighting. We compare the two approaches with three baselines - without adaptation, merging data, and simple interpolation - on Switchboard (SWBD) and Wall Street Journal (WSJ). Experiments show that the mixer model generally performs better than baselines and finetuning. Compared with no adaptation, finetuning and the mixer approach obtain up to relative 11.5% and 14.1% WER reductions on SWBD, respectively. The mixer model also outperforms linear interpolation and merging data. On WSJ, the mixer approach achieves a new state-of-the-art WER result.