# Hierarchical Transformer-based Large-Context End-to-end ASR with Large-Context Knowledge Distillation

arXiv: https://arxiv.org/abs/2102.07935 · HTML: https://mlsanity.com/paper/2102.07935/

## Key facts

- Cited by 12 papers in the map (data through 14 Oct 2026).
- Placed in Speech and audio distillation, one of 12 directions in Knowledge distillation.
- Builds on 19 of its 31 references that are in the map.
- First posted on arXiv 16 Feb 2021.

## Placed in

- Knowledge distillation / [Speech and audio distillation](https://mlsanity.com/distill/speech-and-audio-distillation/)

## Builds on (most cited first, 19 of 19)

- [Attention Is All You Need](https://mlsanity.com/paper/1706.03762/) (2017)
- [Rethinking the Inception Architecture for Computer Vision](https://mlsanity.com/paper/1512.00567/) (2015)
- [SpecAugment: A Simple Data Augmentation Method for Automatic Speech Recognition](https://mlsanity.com/paper/1904.08779/) (2019)
- [On the Variance of the Adaptive Learning Rate and Beyond](https://mlsanity.com/paper/1908.03265/) (2019)
- [A Structured Self-attentive Sentence Embedding](https://mlsanity.com/paper/1703.03130/) (2017)
- [Building End-To-End Dialogue Systems Using Generative Hierarchical Neural Network Models](https://mlsanity.com/paper/1507.04808/) (2015)
- [End-to-End Attention-based Large Vocabulary Speech Recognition](https://mlsanity.com/paper/1508.04395/) (2015)
- [Hierarchical Transformers for Multi-Document Summarization](https://mlsanity.com/paper/1905.13164/) (2019)
- [Improving the Transformer Translation Model with Document-Level Context](https://mlsanity.com/paper/1810.03581/) (2018)
- [Exploiting Cross-Sentence Context for Neural Machine Translation](https://mlsanity.com/paper/1704.04347/) (2017)
- [Advances in Joint CTC-Attention based End-to-End Speech Recognition with a Deep CNN Encoder and RNN-LM](https://mlsanity.com/paper/1706.02737/) (2017)
- [Document Context Neural Machine Translation with Memory Networks](https://mlsanity.com/paper/1711.03688/) (2017)
- [Distilling the Knowledge of BERT for Sequence-to-Sequence ASR](https://mlsanity.com/paper/2008.03822/) (2020)
- [Dialog-context aware end-to-end speech recognition](https://mlsanity.com/paper/1808.02171/) (2018)
- [Learn Spelling from Teachers: Transferring Knowledge from Language Models to Sequence-to-Sequence Speech Recognition](https://mlsanity.com/paper/1907.06017/) (2019)
- [Larger-Context Language Modelling](https://mlsanity.com/paper/1511.03729/) (2015)
- [Sequence-Level Knowledge Distillation for Model Compression of Attention-based Sequence-to-Sequence Speech Recognition](https://mlsanity.com/paper/1811.04531/) (2018)
- [Advances in All-Neural Speech Recognition](https://mlsanity.com/paper/1609.05935/) (2016)
- [Direct Acoustics-to-Word Models for English Conversational Speech Recognition](https://mlsanity.com/paper/1703.07754/) (2017)

## Built on by (most cited first, 12 of 12)

- [Speech Summarization using Restricted Self-Attention](https://mlsanity.com/paper/2110.06263/) (2021)
- [Mokey: Enabling Narrow Fixed-Point Inference for Out-of-the-Box Floating-Point Transformer Models](https://mlsanity.com/paper/2203.12758/) (2022)
- [Accelerating Transducers through Adjacent Token Merging](https://mlsanity.com/paper/2306.16009/) (2023)
- [Conversational Speech Recognition By Learning Conversation-level Characteristics](https://mlsanity.com/paper/2202.07855/) (2022)
- [Leveraging Acoustic Contextual Representation by Audio-textual Cross-modal Learning for Conversational ASR](https://mlsanity.com/paper/2207.01039/) (2022)
- [LongFNT: Long-form Speech Recognition with Factorized Neural Transducer](https://mlsanity.com/paper/2211.09412/) (2022)
- [Unified Autoregressive Modeling for Joint End-to-End Multi-Talker Overlapped Speech Recognition and Speaker Attribute Estimation](https://mlsanity.com/paper/2107.01549/) (2021)
- [Improving Transformer-based Conversational ASR by Inter-Sentential Attention Mechanism](https://mlsanity.com/paper/2207.00883/) (2022)
- [Conversational Speech Recognition by Learning Audio-textual Cross-modal Contextual Representation](https://mlsanity.com/paper/2310.14278/) (2023)
- [The Eloquence team submission for task 1 of MLC-SLM challenge](https://mlsanity.com/paper/2507.19308/) (2025)
- [Promptformer: Prompted Conformer Transducer for ASR](https://mlsanity.com/paper/2401.07360/) (2024)
- [An Efficient Self-Learning Framework For Interactive Spoken Dialog Systems](https://mlsanity.com/paper/2409.10515/) (2024)

## Abstract (arXiv)

We present a novel large-context end-to-end automatic speech recognition (E2E-ASR) model and its effective training method based on knowledge distillation. Common E2E-ASR models have mainly focused on utterance-level processing in which each utterance is independently transcribed. On the other hand, large-context E2E-ASR models, which take into account long-range sequential contexts beyond utterance boundaries, well handle a sequence of utterances such as discourses and conversations. However, the transformer architecture, which has recently achieved state-of-the-art ASR performance among utterance-level ASR systems, has not yet been introduced into the large-context ASR systems. We can expect that the transformer architecture can be leveraged for effectively capturing not only input speech contexts but also long-range sequential contexts beyond utterance boundaries. Therefore, this paper proposes a hierarchical transformer-based large-context E2E-ASR model that combines the transformer architecture with hierarchical encoder-decoder based large-context modeling. In addition, in order to enable the proposed model to use long-range sequential contexts, we also propose a large-context knowledge distillation that distills the knowledge from a pre-trained large-context language model in the training phase. We evaluate the effectiveness of the proposed model and proposed training method on Japanese discourse ASR tasks.
