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Ziel dieser Arbeit war es, eine Software zu entwickeln, die quantitative und qualitative korpuslinguistische Methoden miteinander verbindet. Die Gesamtarbeit besteht daher aus zwei Teilen: einer Open-Source-Software und dem schriftlichen Teil. Der hier vorgelegte schriftliche Teil ist eine vollständige Dokumentation (Handbuch), ergänzt um eigene Publikationen, die im Rahmen des Dissertationsprojekts entstanden. In Kapitel 1.2 Korpora und beispielhafte Fragestellungen (S. 8) erfolgt eine Illustration beispielhafter Forschungsfragen anhand bereitgestellter und im Corpus- Explorer integrierter Korpora. Außerdem werden unter "?? ?? (S. ??)" Analysen mit verschiedensten prototypischen Forschungsfragen verknüpft, die sowohl quantitative als auch qualitative Perspektiven einnehmen. Der CorpusExplorer wurde besonders nutzerfreundlich gestaltet. Dabei ist die Zielgruppe der Software sehr breit defniert: Die Nutzung soll sowohl in der Forschung als auch in der Lehre möglich sein. Daher richtet sich der CorpusExplorer gleichermaßen an Studierende und Forschende mit ihren jeweils spezifschen Bedürfnissen. Die Nutzung für die Forschung zeigt sich (A) an den integrierten Artikeln sowie daran, dass (B) andere Forschende den CorpusExplorer bereits für ihre Arbeit aufgegriffen haben. Der Nutzen für die Lehre wurde mehrfach selbst erprobt und optimiert. Im Lehr-Einsatz ist es wichtig, dass Korpora mit wenigen Mausklicks analysefertig sind und verschiedene Analysen und Visualisierungen direkt genutzt werden können. Studierende erhalten so die Möglichkeit, eigenes Korpusmaterial direkt und selbst auszuwerten. Für Forschende bietet der CorpusExplorer ein sehr breites Funktionsspektrum. Im Vergleich zu anderer (öffentlich verfügbarer) korpuslinguistischer Software verfügt er aktuell über das wohl breiteste Anwendungsspektrum (51 Analysemodule (inkl. weiterentwickelter Verfahren), über 100 unterstützte Dateiformate für Im- und Export, unterschiedliche Tagger mit 69 unterstützten Sprachmodellen). Er kann so in bestehende Skripte, Toolchains und Workflows für sehr unterschiedliche Forschungsfragen integriert werden. Im CorpusExplorer wurden nicht nur bestehende Funktionen gebündelt, es wurden auch bisherige Verfahren weiterentwickelt. Hierzu zählen z. B. (1) die Entwicklung einer eigenen, an korpuslinguistischen Bedürfnissen ausgerichteten Datenbank- Struktur, (2) die Weiterentwicklung bzw. Optimierung des Verfahrens der Kookkurrenz- Analyse hin zu einer quantitativen Kookkurrenz-Analyse (keine Parameter wie Suchfenstergröße oder Suchwort nötig, Berechnung aller Kookkurrenzen zu allen Token in einem Korpus) und (3) die Verknüpfung unterschiedlicher Analyseressourcen, wie z. B. der NGram- und der Kookkurrenz-Analyse.
This thesis describes work in three areas: grammar engineering, computer-assisted language learning and grammar learning. These three parts are connected by the concept of a grammar-based language learning application. Two types of grammars are of concern. The first we call resource grammars, extensive descriptions a natural languages. Part I focuses on this kind of grammars. The other are domain-specific or application-specific grammars. These grammars only describe a fragment of natural language that is determined by the domain of a certain application. Domain-specific grammars are relevant for Part II and Part III. Another important distinction is between humans learning a new natural language using computational grammars (Part II) and computers learning grammars from example sentences (Part III). Part I of this thesis focuses on grammar engineering and grammar testing. It describes the development and evaluation of a computational resource grammar for Latin. Latin is known for its rich morphology and free word order, both have to be handled in a computationally efficient way. A special focus is on methods how computational grammars can be evaluated using corpus data. Such an evaluation is presented for the Latin resource grammar. Part II, the central part, describes a computer-assisted language learning application based on domain-specific grammars. The language learning application demonstrates how computational grammars can be used to guide the user input and how language learning exercises can be modeled as grammars. This allows us to put computational grammars in the center of the design of language learning exercises used to help humans learn new languages. Part III, the final part, is dedicated to a method to learn domain- or application-specific grammars based on a wide-coverage grammar and small sets of example sentences. Here a computer is learning a grammar for a fragment of a natural language from example sentences, potentially without any additional human intervention. These learned grammars can be based e.g. on the Latin resource grammar described in Part II and used as domain-specific lesson grammars in the language learning application described Part II.
This dissertation investigates discourse-pragmatic differences between variably linked arguments appearing in alternating argument structure constructions in the sense of Goldberg (1995) and Kay (manuscript). The properties that are studied include givenness, pragmatic relation (topic/focus), salience of referents, animacy, and others. They derive from the literature on sentence-type constructions such as topicalization and from research on the referential properties of NP form types.
The research carried out here has multiple uses. At the most basic level, it serves as an empirical check on existing characterizations of the pragmatic properties of the relevant arguments that are the result of syntactic and semantic analysis based on introspection alone. For instance, for the epistemic raising alternation involving verbs like seem, the predicted topicality difference between the subjects of the raised and unraised constructions (Langacker 1995) could not be confirmed.
This dissertation also addresses the question what kinds of pragmatic factors, if any, are relevant to argument structure constructions. Based on the evidence of the dative alternation, it does not seem to be the case that the kind of pragmatic influences on argument structure constructions are different or limited compared to the ones found to be relevant to sentence-type constructions.
The kind of research undertaken here can also inform the syntactic and semantic analysis of constructions. In the case of the dative alternation, the discourse-pragmatic characteristics of the variably linked arguments provide evidence that Basilico’s (1998) analysis of the difference between the alternates in terms of VP-shells and a difference between thetic and categorical ‘inner’ predication, on the one hand does not account for all the data and on the other can be re-stated in pragmatic terms other than the thetic-categorical distinction.
In addition to studies of valence alternations, this dissertation also discusses various null instantiation phenomena, which provide further evidence for the need to specify discourse-pragmatic properties as part of argument structure constructions and lexical entries.
Finally, it is suggested that the use of randomly sampled corpus data and statistical modelling throughout this dissertation improves both empirical and analytical coverage.
Manual development of deep linguistic resources is time-consuming and costly and therefore often described as a bottleneck for traditional rule-based NLP. In my PhD thesis I present a treebank-based method for the automatic acquisition of LFG resources for German. The method automatically creates deep and rich linguistic presentations from labelled data (treebanks) and can be applied to large data sets. My research is based on and substantially extends previous work on automatically acquiring wide-coverage, deep, constraint-based grammatical resources from the English Penn-II treebank (Cahill et al.,2002; Burke et al., 2004; Cahill, 2004). Best results for English show a dependency f-score of 82.73% (Cahill et al., 2008) against the PARC 700 dependency bank, outperforming the best hand-crafted grammar of Kaplan et al. (2004). Preliminary work has been carried out to test the approach on languages other than English, providing proof of concept for the applicability of the method (Cahill et al., 2003; Cahill, 2004; Cahill et al., 2005). While first results have been promising, a number of important research questions have been raised. The original approach presented first in Cahill et al. (2002) is strongly tailored to English and the datastructures provided by the Penn-II treebank (Marcus et al., 1993). English is configurational and rather poor in inflectional forms. German, by contrast, features semi-free word order and a much richer morphology. Furthermore, treebanks for German differ considerably from the Penn-II treebank as regards data structures and encoding schemes underlying the grammar acquisition task. In my thesis I examine the impact of language-specific properties of German as well as linguistically motivated treebank design decisions on PCFG parsing and LFG grammar acquisition. I present experiments investigating the influence of treebank design on PCFG parsing and show which type of representations are useful for the PCFG and LFG grammar acquisition tasks. Furthermore, I present a novel approach to cross-treebank comparison, measuring the effect of controlled error insertion on treebank trees and parser output from different treebanks. I complement the cross-treebank comparison by providing a human evaluation using TePaCoC, a new testsuite for testing parser performance on complex grammatical constructions. Manual evaluation on TePaCoC data provides new insights on the impact of flat vs. hierarchical annotation schemes on data-driven parsing. I present treebank-based LFG acquisition methodologies for two German treebanks. An extensive evaluation along different dimensions complements the investigation and provides valuable insights for the future development of treebanks.