Spoken Language Modeling with Duration-Penalized Self-Supervised Units

Fuente: arXiv
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Main Authors: Visser, Nicol, Kamper, Herman
Format: Preprint
Published: 2025
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author Visser, Nicol
Kamper, Herman
author_facet Visser, Nicol
Kamper, Herman
contents Spoken language models (SLMs) operate on acoustic units obtained by discretizing self-supervised speech representations. Although the characteristics of these units directly affect performance, the interaction between codebook size and unit coarseness (i.e., duration) remains unexplored. We investigate SLM performance as we vary codebook size and unit coarseness using the simple duration-penalized dynamic programming (DPDP) method. New analyses are performed across different linguistic levels. At the phone and word levels, coarseness provides little benefit, as long as the codebook size is chosen appropriately. However, when producing whole sentences in a resynthesis task, SLMs perform better with coarser units. In lexical and syntactic language modeling tasks, coarser units also give higher accuracies at lower bitrates. We therefore show that coarser units aren't always better, but that DPDP is a simple and efficient way to obtain coarser units for the tasks where they are beneficial.
format Preprint
id arxiv_https___arxiv_org_abs_2505_23494
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Spoken Language Modeling with Duration-Penalized Self-Supervised Units
Visser, Nicol
Kamper, Herman
Computation and Language
Audio and Speech Processing
Spoken language models (SLMs) operate on acoustic units obtained by discretizing self-supervised speech representations. Although the characteristics of these units directly affect performance, the interaction between codebook size and unit coarseness (i.e., duration) remains unexplored. We investigate SLM performance as we vary codebook size and unit coarseness using the simple duration-penalized dynamic programming (DPDP) method. New analyses are performed across different linguistic levels. At the phone and word levels, coarseness provides little benefit, as long as the codebook size is chosen appropriately. However, when producing whole sentences in a resynthesis task, SLMs perform better with coarser units. In lexical and syntactic language modeling tasks, coarser units also give higher accuracies at lower bitrates. We therefore show that coarser units aren't always better, but that DPDP is a simple and efficient way to obtain coarser units for the tasks where they are beneficial.
title Spoken Language Modeling with Duration-Penalized Self-Supervised Units
topic Computation and Language
Audio and Speech Processing
url https://arxiv.org/abs/2505.23494