SEAM: Bridging the Temporal-Semantic Granularity Gap for LLM-based Speech Recognition

Junseok Oh, Ji-Hwan Kim


Abstract
Speech-LLM integration faces a temporal-semantic granularity gap: speech representations scale with temporal duration while text tokens scale with semantic content. Existing duration-based methods generate embeddings at fixed rates, creating distributional mismatch with LLM pre-training. We propose SEAM (Speech Encoder-Decoder Alignment Module), an encoder-decoder architecture employing variable-rate generation through cross-attention between speech features and text embeddings. SEAM produces embeddings at adaptive rates that closely match natural text distributions while preserving pre-trained knowledge by freezing both speech encoder and LLM. We introduce a multi-stage training strategy and First Token Guidance to improve initial token prediction. SEAM achieves competitive performance on LibriSpeech (2.6%/5.2% WER). More significantly, trained only on LibriSpeech (960h), SEAM achieves 4.7% WER on cross-domain TED-LIUM-v2, demonstrating that integrating LLM’s linguistic knowledge enables effective generalization beyond limited speech training data.
Anthology ID:
2026.findings-eacl.112
Volume:
Findings of the Association for Computational Linguistics: EACL 2026
Month:
March
Year:
2026
Address:
Rabat, Morocco
Editors:
Vera Demberg, Kentaro Inui, Lluís Marquez
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
2135–2144
Language:
URL:
https://preview.aclanthology.org/ingest-eacl/2026.findings-eacl.112/
DOI:
Bibkey:
Cite (ACL):
Junseok Oh and Ji-Hwan Kim. 2026. SEAM: Bridging the Temporal-Semantic Granularity Gap for LLM-based Speech Recognition. In Findings of the Association for Computational Linguistics: EACL 2026, pages 2135–2144, Rabat, Morocco. Association for Computational Linguistics.
Cite (Informal):
SEAM: Bridging the Temporal-Semantic Granularity Gap for LLM-based Speech Recognition (Oh & Kim, Findings 2026)
Copy Citation:
PDF:
https://preview.aclanthology.org/ingest-eacl/2026.findings-eacl.112.pdf
Checklist:
 2026.findings-eacl.112.checklist.pdf