  Recent works have demonstrated success in controlling sentence attributes
($e.g.$, sentiment) and structure ($e.g.$, syntactic structure) based on the
diffusion language model. A key component that drives theimpressive performance
for generating high-quality samples from noise is iteratively denoise for
thousands of steps. While beneficial, the complexity of starting from the noise
and the learning steps has limited its implementation to many NLP real-world
applications. This paper proposes Language Rectified Flow ({\ours}). Our method
is based on the reformulation of the standard probabilistic flow models.
Language rectified flow learns (neural) ordinary differential equation models
to transport between the source distribution and the target distribution, hence
providing a unified and effective solution to generative modeling and domain
transfer. From the source distribution, our language rectified flow yields fast
simulation and effectively decreases the inference time. Experiments on three
challenging fine-grained control tasks and multiple high-quality text editing
show that our method consistently outperforms its baselines. Extensive
experiments and ablation studies demonstrate that our method can be general,
effective, and beneficial for many NLP tasks.
