PhD thesis - School of Informatics - University of Edinburgh

Chapter 1. Introduction 4
Chapter 3: Tracking English Inclusions in German describes an English inclusion
classifier developed for mixed-lingual input text with German as the base language.
It focuses initially on evaluation data preparation and annotation issues, subsequently
providing a complete system description. The chapter also presents an evaluation of
the English inclusion classifier and its components, as well as its performance on two
unseen datasets. The results show that the classifier performs well on new data in dif-
ferent domains and compares well to another state-of-the-art mixed-lingual language
identification approach. The penultimate section describes and discusses parameter
tuning experiments conducted to determine the optimal settings for the classifier. Fi-
nally, the English inclusion classifier is compared to a supervised machine learner.
Chapter 4: System Extension to a New Language describes the adaptation of the
classifier to process French text containing English inclusions. The aim of this chapter
is to illustrate the ease with which the system can be adapted to deal with a new base
language. The chapter first describes data preparation and then explains the work in-
volved in extending various system modules. Finally, a detailed evaluation on unseen
test data and a comparison of the classifier’s performance across languages is presented
and discussed. The results show that the English inclusion classifier not only performs
well on new data in different domains but also successfully fulfils its purpose in differ-
ent language scenarios.
Chapter 5: Parsing English Inclusions concentrates on applying the techniques de-
veloped in the previous two chapters to a real-world task. This chapter presents a series
of experiments on English inclusions and a set of random test suites using a treebank-
induced and a hand-crafted rule-based German grammar parser. The aim here is to
investigate the difficulty that state-of-the-art parsers have with sentences containing
foreign inclusions, thereby determining the reasons for inaccuracy by means of error
analysis and identifying appropriate ways of improving parsing performance. The ul-
timate goal of this chapter is to highlight the oft-forgotten issue of English inclusions
to researchers in the parsing community and motivate them to identify ways of dealing
with inclusions by demonstrating the potential gains in parsing quality.