Publications

Abstract

Although humans are the ultimate “natural language generators”, the area of psycholinguistic modeling has been somewhat underrepresented in recent approaches to Natural Language Generation in computer science. To draw attention to the area and illustrate its potential relevance to Natural Language Generation, I provide an overview of recent work on psycholinguistic modeling of language production together with some key empirical findings, state-of-the-art experimental techniques, and their historical roots. The techniques include analyses of speech-error corpora, chronometric analyses, eyetracking, and neuroimaging.
The overview is built around the issue of cognitive control in natural language generation, concentrating on the production of single words, which is an essential ingredient of the generation of larger utterances. Most of the work exploited the fact that human speakers are good but not perfect at resisting temptation, which has provided some critical clues about the nature of the underlying system.

Abstract

In this paper, I will argue that although the study of multimodal interaction offers exciting new prospects for Human Computer Interaction and human-human communication research, language is the primary form of communication, even in multimodal systems. I will support this claim with theoretical and empirical arguments, mainly drawn from human-human communication research, and will discuss the implications for multimodal communication research and Human-Computer Interaction.

Abstract

Listeners’ signals of recipiency, such as “Mm-hm” or “uh-huh” in English, are the most elementary or minimal “conversational turns” possible. Minimal, because apart from acknowledging recipiency and inviting the speaker to continue with his/her next turn, they do not add any new information to the discourse of the conversation. The goal of this project is to gather cross cultural information on listeners’ feedback behaviour during conversation. Listeners in a conversation usually provide short signals that indicate to the speaker that they are still “with the speaker”. These signals could be verbal (like for instance “mm hm” in English or “hm hm” in Dutch) or nonverbal (visual), like nodding. Often, these signals are produced in overlap with the speaker’s vocalisation. If listeners do not produce these signals, speakers often invite them explicitly (e.g. “are you still there?” in a telephone conversation). Our goal is to investigate what kind of signals are used by listeners of different languages to signal “recipiency” to the speaker.

Abstract

Most of the study of basic emotion expressions has focused on facial expressions and little work has been done to specifically investigate happiness, the only positive of the basic emotions (Ekman & Friesen, 1971). However, a theoretical suggestion has been made that happiness could be broken down into discrete positive emotions, which each fulfil the criteria of basic emotions, and that these would be expressed vocally (Ekman, 1992). To empirically test this hypothesis, 20 participants categorised 80 paralinguistic sounds using the labels achievement, amusement, contentment, pleasure and relief. The results suggest that achievement, amusement and relief are perceived as distinct categories, which subjects accurately identify. In contrast, the categories of contentment and pleasure were systematically confused with other responses, although performance was still well above chance levels. These findings are initial evidence that the positive emotions engage distinct vocal expressions and may be considered to be distinct emotion categories.

Abstract

The ultimate goal of our research is to develop a computational model of human speech recognition that is able to capture the effects of fine-grained acoustic variation on speech recognition behaviour. As part of this work we are investigating automatic feature classifiers that are able to create reliable and accurate transcriptions of the articulatory behaviour encoded in the acoustic speech signal. In the experiments reported here, we compared support vector machines (SVMs) with multilayer perceptrons (MLPs). MLPs have been widely (and rather successfully) used for the task of multi-value articulatory feature classification, while (to the best of our knowledge) SVMs have not. This paper compares the performances of the two classifiers and analyses the results in order to better understand the articulatory representations. It was found that the MLPs outperformed the SVMs, but it is concluded that both classifiers exhibit similar behaviour in terms of patterns of errors.

Abstract

This work focuses on efficient use of the training material by selecting the optimal set of model topologies. We do this by training multiple word models of each word class, based on a subclassification according to a priori knowledge of the training material. We will examine classification criteria with respect to duration of the word, gender of the speaker, position of the word in the utterance, pauses in the vicinity of the word, and combinations of these. Comparative experiments were carried out on a corpus consisting of Dutch spoken connected digit strings and isolated digits, which are recorded in a wide variety of acoustic conditions. The results show, that classification based on gender of the speaker, position of the digit in the string, pauses in the vicinity of the training tokens, and models based on a combination of these criteria perform significantly better than the set with single models per digit.

Abstract

In this paper, we investigate the ability of SpeM, our recognition system based on the combination of an automatic phone recogniser and a wordsearch module, to determine as early as possible during the word recognition process whether a word is likely to be recognised correctly (this we refer to as ‘on-line’ early word recognition). We present two measures that can be used to predict whether a word is correctly recognised: the Bayesian word activation and the amount of available (acoustic) information for a word. SpeM was tested on 1,463 polysyllabic words in 885 continuous speech utterances. The investigated predictors indicated that a word activation that is 1) high (but not too high) and 2) based on more phones is more reliable to predict the correctness of a word than a similarly high value based on a small number of phones or a lower value of the word activation.

Abstract

This presentation will address aspects of the expression of emotion in non-verbal vocal behaviour, specifically attempting to determine the roles of both positive and negative emotions, their acoustic bases, and the extent to which these are recognized in non-Western cultures.

Abstract

Previous studies have indicated that vocal and facial expressions of the ‘basic’ emotions share aspects of processing. Thus amygdala damage compromises the perception of fear and anger from the face and from the voice. In the current study we tested the hypothesis that there exist positive basic emotions, expressed mainly in the voice (Ekman, 1992). Vocal stimuli were produced to express the specific positive emotions of amusement, achievement, pleasure, contentment and relief.

Abstract

This paper presents preliminary remarks on some of the central linguistic means speakers of Kilivila use in expressing their conceptions of space and for referring to objects, persons, and events in space . After a brief characterisation of the language and its speakers, I sketch how specific topological relations are encoded, how motion events are described, and what frames of spatial reference are preferred in what contexts for what means and ends.

Abstract

Human ethologists have shown that humans are both attracted to others and at the same time fear them. They refer to this kind of fear with the technical term ‘social fear’ and claim that “it is alleviated with personal acquaintance but remains a principle characteristic of interpersonal behaviour. As a result, we maintain various degrees of greater distance between ourselves and others depending on the amount of confidence we have in the other” (Eibl-Eibesfeldt 1989: 335). The goal of this task is to conduct exploratory, heuristic research to establish a new subproject that – based on a corpus of video data – will investigate various forms of human spatial behaviour cross-culturally.

Abstract

1. Introduction 2. A generative grammar as an algorithm 3. The semantic component 4. Bibliography 1. Introduction Throughout the 20th century up to the present day grammar and semantics have been uneasy bedfellows. A look at the historical background will make it clear how this curious situation came about. 20th-century linguistics has been characterized by an almost exclusive concern with the structure of words, word groups and sentences. This concern was reinforced, especially on the American side of the Atlantic, by the sudden rise and subsequent dominance of behaviorism during the 1920s. It started in psychology but quickly permeated all the human sciences, including linguistics, until the early 1960s, when it collapsed as suddenly as it had arisen.

Abstract

Presupposition is a semantic device built into natural language to make sentences fit for use in certain contexts but not in others. A sentence carrying a presupposition thus evokes a context in which that presupposition is fulfilled. The study of presupposition was triggered by the behavior of natural language negation, which tends to preserve presuppositions either as invited inferences or as entailments. As the role of discourse became more apparent in semantics, presupposition began to be seen increasingly as a discourse-semantic phenomenon with consequences for the logic of language.

Abstract

The property of presuppositions to be sometimes preserved through embeddings, albeit often in a weakened form, is called projection. The projection problem consists in formulating the conditions under which the presuppositions of an embedded clause (a) are kept as presuppositions of the superordinate structure, or (b) remain as an invited inference that can be overruled by context, or (c) are canceled. Over the past 25 years it has been recognized that the projection problem is to be solved in the context of a wider theory of presupposition and discourse incrementation.

Abstract

Logic was discovered by Aristotle when he saw that the semantic behavior of the negation word not is different in sentences with a definite and in those with a quantified subject term. Until the early 20th century, logic remained firmly language-based, but for the past century it has been mainly a tool in the hands of mathematicians, which has meant an alienation from linguistic reality. With the help of new techniques, it is now possible to revert to the logic of language, which is seen as based on a semantic analysis of the logical words (constants) involved. This new perspective, combined with much improved insights into the semantically defined discourse dependency of natural language sentences, leads to a novel and more functionally oriented approach to logic and to a reappraisal of traditional predicate calculus, whose main fault, undue existential import, evaporates when discourse dependency, in particular the presuppositional aspect, is brought into play. Traditional predicate calculus is seen to have a much greater logical power and a much greater functionality than modern predicate calculus. There is also full isomorphism, neglected in modern logic, between traditional predicate calculus and propositional calculus, which raises the question of any possible deeper causes.

Abstract

Virtual objects are objects thought up by a thinking individual. Although 20th-century philosophy has tried to ban them from ontology, they make it impossible to account for the truth of sentences such as Apollo was worshipped in the island of Delos, in which a property is assigned to the nonexisting, virtual entity Apollo. Such facts are the reason why virtual objects are slowly being recognized again.

Abstract

Some predicates are ‘factive’ in that they induce the presupposition that what is said in their subordinate that clause is true.

Abstract

The term ‘donkey sentences’ derives from the medieval philosopher Walter Burleigh, whose example sentences contain mention of donkeys. The modern philosopher Peter Geach rediscovered Burleigh's sentences and the associated problem. The problem is that natural language anaphoric pronouns are sometimes used in a way that cannot be accounted for in terms of modern predicate calculus. The solution lies in establishing a separate category of anaphoric pronouns that refer via the intermediary of a contextually given antecedent, possibly an existentially quantified expression.

Abstract

A discourse domain D is a form of middle-term memory for the storage of the information embodied in the discourse at hand. The information carried by a new utterance u is added to D (u is incremented to D). The processes involved and the specific structure of D are a matter of ongoing research.

Abstract

Discourse semantics (DSx) is based on the fact that the interpretation of uttered sentences is dependent on and co-determined by the information stored in a specialized middle-term cognitive memory called discourse domain (D). DSx studies the structure and dynamics of Ds and the conditions to be fulfilled by D for proper interpretation. It does so in the light of the truth-conditional criteria for semantics, with an emphasis on intensionality phenomena. It requires the assumption of virtual entities and virtual facts. Any model-theoretic interpretation holds between discourse structures and pre-established verification domains.

Abstract

Aristotle's importance in the professional study of language consists first of all in the fact that he demythologized language and made it an object of rational investigation. In the context of his theory of truth as correspondence, he also provided the first semantic analysis of propositions in that he distinguished two main constituents, the predicate, which expresses a property, and the remainder of the proposition, referring to a substance to which the property is assigned. That assignment is either true or false. Later, the ‘remainder’ was called subject term, and the Aristotelian predicate was identified with the verb in the sentence. The Aristotelian predicate, however, is more like what is now called the ‘comment,’ whereas his remainder corresponds to the topic. Aristotle, furthermore, defined nouns and verbs as word classes. In addition, he introduced the term ‘case’ for paradigmatic morphological variation.

Abstract

There is a growing awareness among theoretical linguists and philosophers of language that the linguistic definition of lexical meanings, which must be learned when one learns a language, underdetermines not only full utterance interpretation but also sentence meaning. The missing information must be provided by cognition – that is, either general encyclopedic or specific situational knowledge. This fact crucially shows the basic insufficiency of current standard model-theoretic semantics as a paradigm for the analysis and description of linguistic meaning.

Abstract

The lexical conditions, also known as satisfaction conditions, of a predicate P are the conditions that must be satisfied by the term referents of P for P applied to these term referents to yield a true sentence. In view of presupposition theory it makes sense to distinguish two categories of lexical conditions, the preconditions that must be satisfied for the sentence to be usable in any given discourse, and the update conditions which must be satisfied for the sentence to yield truth.

Abstract

The widely prevailing view that standard bivalent logic is the only possible sound logical system, imposed by metaphysical necessity, has been shattered by the development of multivalent logics during the 20th century. It is now clear that standard bivalent logic is merely the minimal representative of a wide variety of viable logics with any number of truth values. These viable logics can be subdivided into families. In this article, the Kleene family and the PPCn family are subjected to special examination, as they appear to be most relevant for the study of the logical properties of human language.

Abstract

The results of an eye-tracking experiment are presented in which Dutch listeners' eye movements were monitored as they heard sentences and saw four pictured objects. Participants were instructed to click on the object mentioned in the sentence. In the critical sentences, a stop-initial target (e.g., "pot") was preceded by an [s], thus causing ambiguity regarding whether the sentence refers to a stop-initial or a cluster-initial word (e.g., "spot"). Participants made fewer fixations to the target pictures when the stop and the preceding [s] were cross-spliced from the cluster-initial word than when they were spliced from a different token of the sentence containing the stop-initial word. Acoustic analyses showed that the two versions differed in various measures, but only one of these - the duration of the [s] - correlated with the perceptual effect. Thus, in this context, the [s] duration information is an important factor guiding word recognition.

Abstract

When people request information, they have a variety of means for eliciting the information. In English two of the primary resources for eliciting information include asking questions, making statements about their interlocutor (thereby generating confirmation or revision). But within these types there are a variety of ways that these information elicitors can be designed. The goal of this task is to examine how different languages seek and provide information, the extent to which syntax vs prosodic resources are used (e.g., in questions), and the extent to which the design of information seeking actions and their responses display a structural preference to promote social solidarity.

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 presents a quantitative analysis of the
turn-taking mechanism evidenced in 93 telephone
dialogues that were taken from the 9-million-word
Spoken Dutch Corpus. While the first part of the paper
focuses on the temporal phenomena of turn taking, such
as durations of pauses and overlaps of turns in the
dialogues, the second part explores the discoursefunctional
aspects of utterances in a subset of 8
dialogues that were annotated especially for this
purpose. The results show that speakers adapt their turntaking
behaviour to the interlocutor’s behaviour.
Furthermore, the results indicate that male-male dialogs
show a higher proportion of overlapping turns than
female-female dialogues.

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

On the basis of two-speaker spontaneous conversations, it is shown that the distributions of both pauses and speech-overlaps of telephone and faceto-face dialogues have different statistical properties. Pauses in a face-to-face
dialogue last up to 4 times longer than pauses in telephone conversations in functionally comparable conditions. There is a high correlation (0.88 or larger) between the average pause duration for the two speakers across face-to-face
dialogues and telephone dialogues. The data provided form a first quantitative analysis of the complex turn-taking mechanism evidenced in the dialogues available in the 9-million-word Spoken Dutch Corpus.

Abstract

The Papuan languages of the central Solomon Islands are a negatively defined areal grouping: They are those four or possibly five languages in the central Solomon Islands that do not belong to the Austronesian family. Bilua (Vella Lavella), Touo (Rendova), Lavukaleve (Russell Islands), Savosavo (Savo Island) and possibly Kazukuru (New Georgia) have been identified as non-Austronesian since the early 20th century. However, their affiliations both to each other and to other languages still remain a mystery. Heterogeneous and until recently largely undescribed, they present an interesting departure from what is known both of Austronesian languages in the region and of the Papuan languages of the mainland of New Guinea.

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.