  Split and rephrase is the task of breaking down a sentence into shorter ones
that together convey the same meaning. We extract a rich new dataset for this
task by mining Wikipedia's edit history: WikiSplit contains one million
naturally occurring sentence rewrites, providing sixty times more distinct
split examples and a ninety times larger vocabulary than the WebSplit corpus
introduced by Narayan et al. (2017) as a benchmark for this task. Incorporating
WikiSplit as training data produces a model with qualitatively better
predictions that score 32 BLEU points above the prior best result on the
WebSplit benchmark.
