Esoteric Language Models
Authors: name: Subham Sekhar Sahoo; name: Zhihan Yang; name: Yash Akhauri; name: Johnna Liu; name: Deepansha Singh; name: Zhoujun Cheng; name: Zhengzhong Liu; name: Eric Xing; name: John Thickstun; name: Arash Vahdat
Published: 2025-06-02 17:47:27

Abstract: Diffusion-based language models offer a compelling alternative to
autoregressive (AR) models by enabling parallel and controllable generation.
Among this family of models, Masked Diffusion Models (MDMs) achieve the
strongest performance but still underperform AR models in perplexity and lack
key inference-time efficiency features--most notably, KV caching. In this work,
we introduce Eso-LMs, a new family of models that fuses AR and MDM paradigms,
enabling smooth interpolation between their perplexities while overcoming their
respective limitations. Eso-LMs set a new state of the art on standard language
modeling benchmarks. Crucially, we are the **first to introduce KV caching for
MDMs** while preserving parallel generation, significantly improving inference
efficiency. Combined with an optimized sampling schedule, our method achieves
up to **65x** faster inference than standard MDMs and **4x** faster inference
than prior semi-autoregressive approaches. We provide the code and model
checkpoints on the project page:
[http://s-sahoo.github.io/Eso-LMs](http://s-sahoo.github.io/Eso-LMs)