𝜆-Diffusion Language Models: Controllable Generalization of Continuous and Discrete Diffusion Dynamics

DongNyeong Heo, Hyunmin Song, Taehwan Kim


Abstract
Diffusion language models (DLMs) have emerged as a promising alternative to autoregressive language models. While discrete DLMs achieve strong performance across language generation tasks, continuous DLMs remain relatively underexplored despite their smooth latent-space dynamics. In this work, we present a unified embedding-space interpretation of continuous and discrete DLMs. Within this framework, we analyze continuous diffusion dynamics as a retention channel that preserves intermediate denoising information during sampling. Motivated by this perspective, we propose 𝜆-DLM, which smoothly interpolates between continuous and discrete diffusion dynamics through a controllable parameter 𝜆. By training with randomly sampled 𝜆, a single model generalizes across continuous, discrete, and intermediate diffusion dynamics, unifying diverse retention behaviors within one framework. Unlike prior methods that rely on fixed or self-confidence-guided diffusion dynamics, 𝜆-DLM enables controllable exploitation–exploration trade-offs without retraining. Experiments on LM1B and OWT unconditional generation benchmarks show that 𝜆-DLM consistently outperforms strong baselines. Moreover, varying 𝜆 enables semantically diverse generation without additional training. Compared with temperature sweeps, varying 𝜆 shows a more structured relationship between lexical diversity and sentence-embedding-based mode coverage.
Anthology ID:
2026.findings-emnlp.1117
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
23666–23683
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.1117/
DOI:
Bibkey:
Cite (ACL):
DongNyeong Heo, Hyunmin Song, and Taehwan Kim. 2026. 𝜆-Diffusion Language Models: Controllable Generalization of Continuous and Discrete Diffusion Dynamics. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 23666–23683, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
𝜆-Diffusion Language Models: Controllable Generalization of Continuous and Discrete Diffusion Dynamics (Heo et al., Findings 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.findings-emnlp.1117.pdf