A Survey on Diffusion Language Models
Authors: name: Tianyi Li, name: Mingda Chen, name: Bowei Guo, name: Zhiqiang Shen

Diffusion Language Models (DLMs) are rapidly emerging as a powerful and
promising alternative to the dominant autoregressive (AR) paradigm. By
generating tokens in parallel through an iterative denoising process, DLMs
possess inherent advantages in reducing inference latency and capturing
bidirectional context, thereby enabling fine-grained control over the
generation process. While achieving a several-fold speed-up, recent
advancements have allowed DLMs to show performance comparable to their
autoregressive counterparts, making them a compelling choice for various
natural language processing tasks. In this survey, we provide a holistic
overview of the current DLM landscape. We trace its evolution and relationship
with other paradigms, such as autoregressive and masked language models, and
cover both foundational principles and state-of-the-art models. Our work offers
an up-to-date, comprehensive taxonomy and an in-depth analysis of current
techniques, from pre-training strategies to advanced post-training methods.
Another contribution of this survey is a thorough review of DLM inference
strategies and optimizations, including improvements in decoding parallelism,
caching mechanisms, and generation quality. We also highlight the latest
approaches to multimodal extensions of DLMs and delineate their applications
across various practical scenarios. Furthermore, our discussion addresses the
limitations and challenges of DLMs, including efficiency, long-sequence
handling, and infrastructure requirements, while outlining future research
directions to sustain progress in this rapidly evolving field. Project GitHub
is available at https://github.com/VILA-Lab/Awesome-DLMs.