A Treebank-based Investigation of IPP-triggering Verbs in Dutch

Experiments on Dependency Parsing of Urdu
Riyaz Ahmad Bhat, Sambhav Jain and Dipti Misra Sharma
Language Technology Research Center, IIIT-Hyderabad, India
{riyaz.bhat|sambhav.jain}@research.iiit.ac.in, dipti@iiit.ac.in
Abstract
In this paper, we present our parsing efforts for Urdu, a South Asian language
with rich morphology. In this effort we tried to identify the important aspects
of the morphology in Urdu which could be exploited for efficient syntactic
parsing. The most important feature is the presence of case clitics on nominals
which mark the kind of relation they bear to their heads. In Urdu, unlike
a positioned language, arguments of the verb are expressed not through their
absolute position in the sentence but through the morphology they carry. Experiments
using the Urdu dependency treebank (UDT) show the significant
impact of the case markers on parsing accuracy of Urdu.
In this paper we have experimented with dependency parsing of Urdu
using the Urdu Dependency Tree-bank (UDT). In UDT there are 3226 sentences
(approx. 0.1M words) annotated at multiple levels viz morphological,
part-of-speech (POS), chunk and dependency levels. Apart from parsing experiments
we also reported some of the problem areas and issues concerning
the dependency parsing of Urdu.
1 Introduction
Parsing morphologically rich languages (MRLs) like Arabic, Czech, Turkish, etc.,
is a hard and challenging task [9]. A large inventory of word-forms, higher degrees
of argument scrambling, discontinuous constituents, long distance dependencies
and case syncretism are some of the challenges which any statistical parser has to
met for efficient parsing of MRLs. Due to the flexible word order of MRLs, dependency
representations are preferred over constituency for their syntactic analysis.
The dependency representations do not constraint the order of words in a sentence
and are thus better suited for the flexible ordering of words in such languages. Like
any other MRL, Indian languages are rich in morphology and allow higher degrees
of argument scrambling. [1] have proposed a dependency based annotation scheme
for the syntactic analysis of Indian languages. Currently a number of dependency
tree-banks are under development following the annotation scheme. Urdu treebank
is one among the tree-banks under development which we have used in this work
[3].
In recent times the availability of large scale syntactic tree-banks has led to a
manifold increase in the development of data driven parsers. CoNLL shared task
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