Publications

Abstract

The classification of texts and pieces of texts uses the occurrence of, combinations of, words as an important indicator. Not every word or each combination of words gives a clear indication of the classification of a piece of text. Research has been done on methods that select some words or combinations of words that are more indicative of the type of a piece of text. These words or combinations of words are selected from the words and word-groups as they occur in the texts. These more indicative words or combinations of words we call ¿cue-phrases¿. The goal of these methods is to select the most indicative cue-phrases first. The collection of selected words and/or combinations thereof can then be used for training the classification system. To test these selection methods, a number of experiments has been done on a corpus containing cookbook recipes and on a corpus of four-participant meetings. To perform these experiments, a computer program was written. On the recipe corpus we looked at classifying the sentences into different types. Some examples of these types include ¿requirement¿ and ¿instruction¿. On the four-person meeting corpus we tried to learn, using only lexical features, whether a sentence is addressed to an individual or a group. The experiments on the recipe corpus produced good results that showed that, a number of, the used cue-phrase selection methods are suitable for feature selection. The experiments on the four-person meeting corpus where less successful in terms of performance off the classification task. We did see comparable patterns in selection methods, and considering the results of Jovanovic we can conclude that different features are needed for this particular classification task. One of the original goals was to look at ¿addressee¿ in discussions. Are sentences more often addressed to individuals inside discussions compared to outside discussions? However, in order to be able to accomplish this, we must first identify the segments of the text that are discussions. It proved hard to come to a reliable specification of discussions, and our initial definition wasn¿t sufficient.

Abstract

This paper describes ongoing research aiming at the description of variation in speech as represented by asynchronous articulatory features. We will first illustrate how distances in the articulatory feature space can be used for event detection along speech trajectories in this space. The temporal structure imposed by the cosine distance in articulatory feature space coincides to a large extent with the manual segmentation on phone level. The analysis also indicates that the articulatory feature representation provides better such alignments than the MFCC representation does. Secondly, we will present first results that indicate that articulatory features can be used to probe for acoustic differences in the onsets of Dutch singulars and plurals.

Abstract

This paper builds on previous work that aims at unraveling the structure of the speech signal by means of using probabilistic representations. The context of this work is a multi-pass speech recognition system in which a phone lattice is created and used as a basis for a lexical search in which symbolic mismatches are allowed at certain costs. The focus is on the optimization of the costs of phone insertions, deletions and substitutions that are used in the lexical decoding pass. Two optimization approaches are presented, one related to a multi-pass computational model for human speech recognition, the other based on a decoding in which Bayes’ risks are minimized. In the final section, the advantages of these optimization methods are discussed and compared.

Abstract

This work presents a salvage grammar of the Biri language of Eastern Central Queensland, a Pama-Nyungan language belonging to the large Maric subgroup. As the language is no longer used, the grammatical description is based on old written sources and on recordings made by linguists in the 1960s and 1970s. Biri is in many ways typical of the Pama-Nyungan languages of Southern Queensland. It has split case marking systems, marking nouns according to an ergative/absolutive system and pronouns according to a nominative/accusative system. Unusually for its area, Biri also has bound pronouns on its verb, cross-referencing the person, number and case of core participants. As far as it is possible, the grammatical discussion is ‘theory neutral’. The first four chapters deal with the phonology, morphology, and syntax of the language. The last two chapters contain a substantial discussion of Biri’s place in the Pama-Nyungan family. In chapter 6 the numerous dialects of the Biri language are discussed. In chapter 7 the close linguistic relationship between Biri and the surrounding languages is examined.

Abstract

This book provides an overview of the grammatical structure of the language Yurakaré, an unclassified and previously undescribed language of central Bolivia. It consists of 8 chapters, each describing different aspects of the language. Chapter 1 is an introduction to the Yurakaré people and their language. Chapter 2 describes the phonology of the language, from the individual sounds to the stress system. In chapter 3 the morphology of Yurakaré is introduced, i.e. the parts of speech, and the different morphological processes. Chapter 4 is a description of the noun phrase and contains information about nouns, adjectives, postpositions and quantifiers. It also discusses the categories associated with the noun phrase in Yurakaré, such as number, possession, collectivity/distributivity, diminutive. In chapter 5, called 'Verbal agreement, voice and valency' there is a description of the argument structure of predicates, how arguments are expressed and how argument structure can be altered by means of voice and valency-changing operations such as applicatives, causative and middle voice. In chapter 6 there is an overview of verbal morphology, apart from the morphology associated with voice, valency and cross-reference discussed in chapter 5. There is also a description of adverbs in the language in this chapter. Chapter 7 discusses formal and functional properties of modal and aspectual enclitics. In chapter 8, finally, the structure of the clause (both simplex and complex) is discussed, including the switch-reference system and word order. The book ends with two text samples.

Abstract

Sign Language of the Netherlands (NGT) is a visual-gestural language in which linguistic information is conveyed through manual as well as non-manual channels; not only the hands, but also body position, head position and facial expression are important for the language structure. Facial expressions serve grammatical functions in the marking of topics, yes/no questions, and wh-questions (Coerts, 1992). Furthermore, facial expression is used nonlinguistically in the expression of affect (Ekman, 1979). Consequently, at the phonetic level obligatory marking of grammar using facial expression may conflict with the expression of affect. In this study, I investigated the interplay of linguistic and affective functions of brow movements in NGT. Three hypotheses were tested in this thesis. The first is that the affective markers of eyebrows would dominate over the linguistic markers. The second hypothesis predicts that the grammatical markers dominate over the affective brow movements. A third possibility is that a Phonetic Sum would occur in which both functions are combined simultaneously. I elicited sentences combining grammatical and affective functions of eyebrows using a randomised design. Five sentence types were included: declarative sentences, topic sentences, yes-no questions, wh-questions with the wh-sign sentence-final and wh-questions with the wh-sign sentence-initial. These sentences were combined with neutral, surprised, angry, and distressed affect. The brow movements were analysed using the Facial Action Coding System (Ekman, Friesen, & Hager, 2002a). In these sentences, the eyebrows serve a linguistic function, an affective function, or both. One of the possibilities in the latter cases was that a Phonetic Sum would occur that combines both functions simultaneously. Surprisingly, it was found that a Phonetic Sum occurs in which the phonetic weight of Action Unit 4 appears to play an important role. The results show that affect displays may alter question signals in NGT.

Abstract

Recent studies using phoneme detection tasks have shown that spoken-language processing is neither facilitated nor interfered with by optional assimilation, but is inhibited by violation of obligatory assimilation. Interpretation of these results depends on an assessment of their generality, specifically, whether they also obtain when listeners are processing nonnative language. Two separate experiments are presented in which native listeners of German and native listeners of Dutch had to detect a target fricative in legal monosyllabic Dutch nonwords. All of the nonwords were correct realisations in standard Dutch. For German listeners, however, half of the nonwords contained phoneme strings which violate the German fricative assimilation rule. Whereas the Dutch listeners showed no significant effects, German listeners detected the target fricative faster when the German fricative assimilation was violated than when no violation occurred. The results might suggest that violation of assimilation rules does not have to make processing more difficult per se.

Abstract

Utilization of computer tools in linguistic research has gained importance with the maturation of media frameworks for the handling of digital audio and video. The increased use of these tools in gesture, sign language and multimodal interaction studies has led to stronger requirements on the flexibility, the efficiency and in particular the time accuracy of annotation tools. This paper describes the efforts made to make ELAN a tool that meets these requirements, with special attention to the developments in the area of time accuracy. In subsequent sections an overview will be given of other enhancements in the latest versions of ELAN, that make it a useful tool in multimodality research.

Abstract

A number of serious reasons will convince an increasing amount of researchers to store their relevant material in centers which we will call "language resource archives". They combine the duty of taking care of long-term preservation as well as the task to give access to their material to different user groups. Access here is meant in the sense that an active interaction with the data will be made possible to support the integration of new data, new versions or commentaries of all sort. Modern Language Resource Archives will have to adhere to a number of basic principles to fulfill all requirements and they will have to be involved in federations to create joint language resource domains making it even more simple for the researchers to access the data. This paper makes an attempt to formulate the essential pillars language resource archives have to adhere to.