Measuring the Redundancy of Decoder Layers in SpeechLLMs

Fuente: arXiv
Guardado en:
Detalles Bibliográficos
Autores principales: Moumen, Adel, Sun, Guangzhi, Woodland, Philip C
Formato: Preprint
Publicado: 2026
Materias:
Acceso en línea:
Etiquetas: Agregar Etiqueta
Sin Etiquetas, Sea el primero en etiquetar este registro!
_version_ 1866912944830283776
author Moumen, Adel
Sun, Guangzhi
Woodland, Philip C
author_facet Moumen, Adel
Sun, Guangzhi
Woodland, Philip C
contents Speech Large Language Models route speech encoder representations into an LLM decoder that typically accounts for over 90% of total parameters. We study how much of this decoder capacity is actually needed for speech tasks. Across two LLM families and three scales (1-8B), we show that decoder redundancy is largely inherited from the pretrained LLM: text and speech inputs yield similar redundant blocks. We then measure excess capacity by pruning decoder layers and analysing post-pruning healing to increase robustness. Our findings show that 7-8B models retain good ASR performance with only 60% of decoder layers, and the same trend extends to smaller scales with reduced pruning tolerance. We then generalise to speech translation, and show that the same blocks of layers are redundant across speech encoders, tasks and languages, indicating that a more global redundancy structure exists, enabling a single pruned and multi-tasks SpeechLLM backbone to be deployed.
format Preprint
id arxiv_https___arxiv_org_abs_2603_05121
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Measuring the Redundancy of Decoder Layers in SpeechLLMs
Moumen, Adel
Sun, Guangzhi
Woodland, Philip C
Computation and Language
Artificial Intelligence
Speech Large Language Models route speech encoder representations into an LLM decoder that typically accounts for over 90% of total parameters. We study how much of this decoder capacity is actually needed for speech tasks. Across two LLM families and three scales (1-8B), we show that decoder redundancy is largely inherited from the pretrained LLM: text and speech inputs yield similar redundant blocks. We then measure excess capacity by pruning decoder layers and analysing post-pruning healing to increase robustness. Our findings show that 7-8B models retain good ASR performance with only 60% of decoder layers, and the same trend extends to smaller scales with reduced pruning tolerance. We then generalise to speech translation, and show that the same blocks of layers are redundant across speech encoders, tasks and languages, indicating that a more global redundancy structure exists, enabling a single pruned and multi-tasks SpeechLLM backbone to be deployed.
title Measuring the Redundancy of Decoder Layers in SpeechLLMs
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2603.05121