Mixture-of-Experts with Intermediate CTC Supervision for Accented Speech Recognition

Fuente: arXiv
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Main Authors: Lee, Wonjun, Kim, Hyounghun, Lee, Gary Geunbae
Format: Preprint
Published: 2026
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author Lee, Wonjun
Kim, Hyounghun
Lee, Gary Geunbae
author_facet Lee, Wonjun
Kim, Hyounghun
Lee, Gary Geunbae
contents Accented speech remains a persistent challenge for automatic speech recognition (ASR), as most models are trained on data dominated by a few high-resource English varieties, leading to substantial performance degradation for other accents. Accent-agnostic approaches improve robustness yet struggle with heavily accented or unseen varieties, while accent-specific methods rely on limited and often noisy labels. We introduce Moe-Ctc, a Mixture-of-Experts architecture with intermediate CTC supervision that jointly promotes expert specialization and generalization. During training, accent-aware routing encourages experts to capture accent-specific patterns, which gradually transitions to label-free routing for inference. Each expert is equipped with its own CTC head to align routing with transcription quality, and a routing-augmented loss further stabilizes optimization. Experiments on the Mcv-Accent benchmark demonstrate consistent gains across both seen and unseen accents in low- and high-resource conditions, achieving up to 29.3% relative WER reduction over strong FastConformer baselines.
format Preprint
id arxiv_https___arxiv_org_abs_2602_01967
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Mixture-of-Experts with Intermediate CTC Supervision for Accented Speech Recognition
Lee, Wonjun
Kim, Hyounghun
Lee, Gary Geunbae
Computation and Language
Artificial Intelligence
Accented speech remains a persistent challenge for automatic speech recognition (ASR), as most models are trained on data dominated by a few high-resource English varieties, leading to substantial performance degradation for other accents. Accent-agnostic approaches improve robustness yet struggle with heavily accented or unseen varieties, while accent-specific methods rely on limited and often noisy labels. We introduce Moe-Ctc, a Mixture-of-Experts architecture with intermediate CTC supervision that jointly promotes expert specialization and generalization. During training, accent-aware routing encourages experts to capture accent-specific patterns, which gradually transitions to label-free routing for inference. Each expert is equipped with its own CTC head to align routing with transcription quality, and a routing-augmented loss further stabilizes optimization. Experiments on the Mcv-Accent benchmark demonstrate consistent gains across both seen and unseen accents in low- and high-resource conditions, achieving up to 29.3% relative WER reduction over strong FastConformer baselines.
title Mixture-of-Experts with Intermediate CTC Supervision for Accented Speech Recognition
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2602.01967