  To facilitate future research in unsupervised induction of syntactic
structure and to standardize best-practices, we propose a tagset that consists
of twelve universal part-of-speech categories. In addition to the tagset, we
develop a mapping from 25 different treebank tagsets to this universal set. As
a result, when combined with the original treebank data, this universal tagset
and mapping produce a dataset consisting of common parts-of-speech for 22
different languages. We highlight the use of this resource via two experiments,
including one that reports competitive accuracies for unsupervised grammar
induction without gold standard part-of-speech tags.
