Insights into Non-projectivity in Hindi

Large scale efforts are underway to create dependency treebanks and parsers for Hindi and other Indian languages. Hindi, being a morphologically rich, flexible word order language, brings challenges such as handling non-projectivity in parsing. In this work, we look at non-projectivity in Hyderabad Dependency Treebank (HyDT) for Hindi. Non-projectivity has been analysed from two perspectives: graph properties that restrict non-projectivity and linguistic phenomenon behind non-projectivity in HyDT. Since Hindi has ample instances of non-projectivity (14% of all structures in HyDT are non-projective), it presents a case for an in depth study of this phenomenon for a better insight, from both of these perspectives. We have looked at graph constriants like planarity, gap degree, edge degree and well-nestedness on structures in HyDT. We also analyse non-projectivity in Hindi in terms of various linguistic parameters such as the causes of non-projectivity, its rigidity (possibility of reordering) and whether the reordered construction is the natural one.

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