An annotation scheme and gold standard for Dutch-English word alignment

The importance of sentence-aligned parallel corpora has been widely acknowledged. Reference corpora in which sub-sentential translational correspondences are indicated manually are more labour-intensive to create, and hence less wide-spread. Such manually created reference alignments - also called Gold Standards - have been used in research projects to develop or test automatic word alignment systems. In most translations, translational correspondences are rather complex; for example word-by-word correspondences can be found only for a limited number of words. A reference corpus in which those complex translational correspondences are aligned manually is therefore also a useful resource for the development of translation tools and for translation studies. In this paper, we describe how we created a Gold Standard for the Dutch-English language pair. We present the annotation scheme, annotation guidelines, annotation tool and inter-annotator results. To cover a wide range of syntactic and stylistic phenomena that emerge from different writing and translation styles, our Gold Standard data set contains texts from different text types. The Gold Standard will be publicly available as part of the Dutch Parallel Corpus

wEBMT: developing and validating an example-based machine translation system using the world wide web

We have developed an example-based machine translation (EBMT) system that uses the World Wide Web for two different purposes: First, we populate the system’s memory with translations gathered from rule-based MT systems located on the Web. The source strings input to these systems were extracted automatically from an extremely small subset of the rule types in the Penn-II Treebank. In subsequent stages, the (source, target) translation pairs obtained are automatically transformed into a series of resources that render the translation process more successful. Despite the fact that the output from on-line MT systems is often faulty, we demonstrate in a number of experiments that when used to seed the memories of an EBMT system, they can in fact prove useful in generating translations of high quality in a robust fashion. In addition, we demonstrate the relative gain of EBMT in comparison to on-line systems. Second, despite the perception that the documents available on the Web are of questionable quality, we demonstrate in contrast that such resources are extremely useful in automatically postediting translation candidates proposed by our system

Sub-sentential alignment of translational correspondences

The focus of this thesis is sub-sentential alignment, i.e. the automatic alignment of translational correspondences below sentence level. The system that we developed takes as its input sentence-aligned parallel texts and aligns translational correspondences at the sub-sentential level, which can be words, word groups or chunks. The research described in this thesis aims to be of value to the developers of computer-assisted translation tools and to human translators in general. Two important aspects of this research are its focus on different text types and its focus on precision. In order to cover a wide range of syntactic and stylistic phenomena that emerge from different writing and translation styles, we used parallel texts of different text types. As the intended users are ultimately human translators, our explicit aim was to develop a model that aligns segments with a very high precision. This thesis consists of three major parts. The first part is introductory and focuses on the manual annotation, the resources used and the evaluation methodology. The second part forms the main contribution of this thesis and describes the sub-sentential alignment system that was developed. In the third part, two different applications are discussed. Although the global architecture of our sub-sentential alignment module is language-independent, the main focus is on the English-Dutch language pair. At the beginning of the research project, a Gold Standard was created. The manual reference corpus contains three different types of links: regular links for straightforward correspondences, fuzzy links for translation-specific shifts of various kinds, and null links for words for which no correspondence could be indicated. The different writing and translation styles in the different text types was reflected in the number of regular, fuzzy and null links. The sub-sentential alignment system is conceived as a cascaded model consisting of two phases. In the first phase, anchor chunks are linked on the basis of lexical correspondences and syntactic similarity. In the second phase, we use a bootstrapping approach to extract language-pair specific translation patterns. The alignment system is chunk-driven and requires only shallow linguistic processing tools for the source and the target languages, i.e. part-of-speech taggers and chunkers. To generate the lexical correspondences, we experimented with two different types of bilingual dictionaries: a handcrafted bilingual dictionary and probabilistic bilingual dictionaries. In the bootstrapping experiments, we started from the precise GIZA++ intersected word alignments. The proposed system improves the recall of the intersected GIZA++ word alignments without sacrificing precision, which makes the resulting alignments more useful for incorporation in CAT-tools or bilingual terminology extraction tools. Moreover, the system's ability to align discontiguous chunks makes the system useful for languages containing split verbal constructions and phrasal verbs. In the last part of this thesis, we demonstrate the usefulness of the sub-sentential alignment module in two different applications. First, we used the sub-sentential alignment module to guide bilingual terminology extraction on three different language pairs, viz. French-English, French-Italian and French-Dutch. Second, we compare the performance of our alignment system with a commercial sub-sentential translation memory system

Idiom treatment experiments in machine translation

Idiomatic expressions pose a particular challenge for the today\u27;s Machine Translation systems, because their translation mostly does not result literally, but logically. The present dissertation shows, how with the help of a corpus, and morphosyntactic rules, such idiomatic expressions can be recognized and finally correctly translated. The work leads the reader in the first chapter generally to the field of Machine Translation and following that, it focuses on the special field of Example-based Machine Translation. Next, an important part of the doctoral thesis dissertation is devoted to the theory of idiomatic expressions. The practical part of the thesis describes how the hybrid Example-based Machine Translation system METIS-II, with the help of morphosyntactic rules, is able to correctly process certain idiomatic expressions and finally, to translate them. The following chapter deals with the function of the transfer system CAT2 and its handling of the idiomatic expressions. The last part of the thesis includes the evaluation of three commercial systems, namely SYSTRAN, T1 Langenscheidt, and Power Translator Pro, with respect to continuous and discontinuous idiomatic expressions. For this, both small corpora and a part of the extensive corpus Europarl and the Digital Lexicon of the German Language in 20th century were processed, firstly manually and then automatically. The dissertation concludes with results from this evaluation.Idiomatische Redewendungen stellen für heutige maschinelle Übersetzungssysteme eine besondere Herausforderung dar, da ihre Übersetzung nicht wörtlich, sondern stets sinngemäß erfolgen muss. Die vorliegende Dissertation zeigt, wie mit Hilfe eines Korpus sowie morphosyntaktischer Regeln solche idiomatische Redewendungen erkannt und am Ende richtig übersetzt werden können. Die Arbeit führt den Leser im ersten Kapitel allgemein in das Gebiet der Maschinellen Übersetzung ein und vertieft im Anschluss daran das Spezialgebiet der Beispielbasierten Maschinellen Übersetzung. Im Folgenden widmet sich ein wesentlicher Teil der Doktorarbeit der Theorie über idiomatische Redewendungen. Der praktische Teil der Arbeit beschreibt wie das hybride Beispielbasierte Maschinelle Übersetzungssystem METIS-II mit Hilfe von morphosyntaktischen Regeln befähigt wurde, bestimmte idiomatische Redewendungen korrekt zu bearbeiten und am Ende zu übersetzen. Das nachfolgende Kapitel behandelt die Funktion des Transfersystems CAT2 und dessen Umgang mit idiomatischen Wendungen. Der letzte Teil der Arbeit beinhaltet die Evaluation von drei kommerzielle Systemen, nämlich SYSTRAN, T1 Langenscheidt und Power Translator Pro, in Bezug auf deren Umgang mit kontinuierlichen und diskontinuierlichen idiomatischen Redewendungen. Hierzu wurden sowohl kleine Korpora als auch ein Teil des umfangreichen Korpus Europarl und des Digatalen Wörterbuchs der deutschen Sprache des 20. Jh. erst manuell und dann maschinell bearbeitet. Die Dissertation wird mit Folgerungen aus der Evaluation abgeschlossen