Evaluating Translational Correspondence using Annotation Projection

Recently, statistical machine translation models have begun to take advantage of higherlevel linguistic structures such as syntactic dependencies. Underlying these models is an
assumption about the directness of translational correspondence between sentences in the
two languages; however, the extent to which this assumption is valid and useful is not well
understood. In this paper, we present an empirical study that quantifies the degree to
which syntactic dependencies are preserved when parses are projected directly from En-
glish to Chinese. Our results show that although the direct correspondence assumption
is often too restrictive, a small set of principled, elementary linguistic transformations
can boost the quality of the projected Chinese parses by 76% relative to the unimproved
baseline.