Publications

Abstract

Disfluency is a common characteristic of spontaneously produced speech. Disfluencies (e.g., silent pauses, filled pauses [uh’s and uhm’s], corrections, repetitions, etc.) occur in both native and non-native speech. There appears to be an apparent contradiction between claims from the evaluative and cognitive approach to fluency. On the one hand, the evaluative approach shows that non-native disfluencies have a negative effect on listeners’ subjective fluency impressions. On the other hand, the cognitive approach reports beneficial effects of native disfluencies on cognitive processes involved in speech comprehension, such as prediction and attention.

This dissertation aims to resolve this apparent contradiction by combining the evaluative and cognitive approach. The reported studies target both the evaluation (Chapters 2 and 3) and the processing of fluency (Chapters 4 and 5) in native and non-native speech. Thus, it provides an integrative account of native and non-native fluency perception, informative to both language testing practice and cognitive psycholinguists. The proposed account of fluency perception testifies to the notion that speech performance matters: communication through spoken language does not only depend on what is said, but also on how it is said and by whom.

Abstract

The fluent production of speech is a very complex human skill. It requires the coordination of several articulatory subsystems. The instructions that lead articulatory movements to execution are the result of the interplay of speech production levels that operate above the articulatory network. During the process of word-form encoding, the groundwork for the articulatory programs is prepared which then serve the articulators as basic units. This thesis investigated whether or not syllables form the basis for the articulatory programs and in particular whether or not these syllable programs are stored, separate from the store of the lexical word-forms. It is assumed that syllable units are stored in a so-called 'mental syllabary'. The main goal of this thesis was to find evidence of the syllable playing a functionally important role in speech production and for the assumption that syllables are stored units. In a variant of the implicit priming paradigm, it was investigated whether information about the syllabic structure of a target word facilitates the preparation (advanced planning) of a to-be-produced utterance. These experiments yielded evidence for the functionally important role of syllables in speech production. In a subsequent row of experiments, it could be demonstrated that the production of syllables is sensitive to frequency. Syllable frequency effects provide strong evidence for the notion of a mental syllabary because only stored units are likely to exhibit frequency effects. In a last study, effects of syllable preparation and syllable frequency were investigated in a combined study to disentangle the two effects. The results of this last experiment converged with those reported for the other experiments and added further support to the claim that syllables play a core functional role in speech production and are stored in a mental syllabary.

Abstract

Children learn their mother tongue spontaneously and effortlessly through communicative interaction with their environment; they do not have to be taught explicitly or learn how to learn first. The ambient language to which children are exposed, however, is highly variable and arguably deficient with regard to the learning target. Nonetheless, most normally developing children learn their native language rapidly and with ease. To explain this accomplishment, many theories of acquisition posit innate constraints on learning, or even a biological endowment for language which is specific to language. Usage-based theories, on the other hand, place more emphasis on the role of experience and domain-general learning mechanisms than on innate language-specific knowledge. But languages are lexically open and combinatorial in structure, so no amount of experience covers their expressivity. Usage-based theories therefore have to explain how children can generalize the properties of their linguistic input to an adult-like grammar. In this thesis I provide an explicit computational mechanism with which usage-based theories of language can be tested and evaluated. The focus of my work lies on complex syntax and the human ability to form sentences which express more than one proposition by means of relativization. This `capacity for recursion' is a hallmark of an adult grammar and, as some have argued, the human language faculty itself. The manuscript is organized as follows. In the second chapter, I give an overview of results that characterize the properties of neural networks as mathematical objects and review previous attempts at modelling the acquisition of complex syntax with such networks. The chapter introduces the conceptual landscape in which the current work is located. In the third chapter, I argue that the construction and use of meaning is essential in child language acquisition and adult processing. Neural network models need to incorporate this dimension of human linguistic behavior. I introduce the Dual-path model of sentence production and syntactic development which is able to represent semantics and learns from exposure to sentences paired with their meaning (cf. Chang et al. 2006). I explain the architecture of this model, motivate critical assumptions behind its design, and discuss existing research using this model. The fourth chapter describes and compares several extensions of the basic architecture to accommodate the processing of multi-clause utterances. These extensions are evaluated against computational desiderata, such as good learning and generalization performance and the parsimony of input representations. A single-best solution for encoding the meaning of complex sentences with restrictive relative clauses is identified, which forms the basis for all subsequent simulations. Chapter five analyzes the learning dynamics in more detail. I first examine the model's behavior for different relative clause types. Syntactic alternations prove to be particularly difficult to learn because they complicate the meaning-to-form mapping the model has to acquire. In the second part, I probe the internal representations the model has developed during learning. It is argued that the model acquires the argument structure of the construction types in its input language and represents the hierarchical organization of distinct multi-clause utterances. The juice of this thesis is contained in chapters six to eight. In chapter six, I test the Dual-path model's generalization capacities in a variety of tasks. I show that its syntactic representations are sufficiently transparent to allow structural generalization to novel complex utterances. Semantic similarities between novel and familiar sentence types play a critical role in this task. The Dual-path model also has a capacity for generalizing familiar words to novel slots in novel constructions (strong semantic systematicity). Moreover, I identify learning conditions under which the model displays recursive productivity. It is argued that the model's behavior is consistent with human behavior in that production accuracy degrades with depth of embedding, and right-branching is learned faster than center-embedding recursion. In chapter seven, I address the issue of learning complex polar interrogatives in the absence of positive exemplars in the input. I show that the Dual-path model can acquire the syntax of these questions from simpler and similar structures which are warranted in a child's linguistic environment. The model's errors closely match children's errors, and it is suggested that children might not require an innate learning bias to acquire auxiliary fronting. Since the model does not implement a traditional kind of language-specific universal grammar, these results are relevant to the poverty of the stimulus debate. English relative clause constructions give rise to similar performance orderings in adult processing and child language acquisition. This pattern matches the typological universal called the noun phrase accessibility hierarchy. I propose an input-based explanation of this data in chapter eight. The Dual-path model displays this ordering in syntactic development when exposed to plausible input distributions. But it is possible to manipulate and completely remove the ordering by varying properties of the input from which the model learns. This indicates, I argue, that patterns of interference and facilitation among input structures can explain the hierarchy when all structures are simultaneously learned and represented over a single set of connection weights. Finally, I draw conclusions from this work, address some unanswered questions, and give a brief outlook on how this research might be continued.

Abstract

Background Stroke-induced aphasia is associated with adverse effects on quality of life and the ability to return to work. However, the predictors of recovery are still poorly understood. Anatomical variability of the arcuate fasciculus, connecting Broca’s and Wernicke’s areas, has been reported in the healthy population using diffusion tensor imaging tractography. In about 40% of the population the arcuate fasciculus is bilateral and this pattern is advantageous for certain language related functions, such as auditory verbal learning (Catani et al. 2007). Methods In this prospective longitudinal study, anatomical predictors of post-stroke aphasia recovery were investigated using diffusion tractography and arterial spin labelling. Patients An 18-subject strong aphasia cohort with first-ever unilateral left hemispheric middle cerebral artery infarcts underwent post stroke language (mean 5±5 days) and neuroimaging (mean 10±6 days) assessments and neuropsychological follow-up at six months. Ten of these patients were available for reassessment one year after symptom onset. Aphasia was assessed with the Western Aphasia Battery, which provides a global measure of severity (Aphasia Quotient, AQ). Results Better recover from aphasia was observed in patients with a right arcuate fasciculus [beta=.730, t(2.732), p=.020] (tractography) and increased fractional anisotropy in the right hemisphere (p<0.05) (Tract-based spatial statistics). Further, an increase in left hemisphere perfusion was observed after one year (p<0.01) (perfusion). Lesion analysis identified maximal overlay in the periinsular white matter (WM). Lesion-symptom mapping identified damage to periinsular structure as predictive for overall aphasia severity and damage to frontal lobe white matter as predictive of repetition deficits. Conclusion These findings suggest an important role for the right hemisphere language network in recovery from aphasia after left hemispheric stroke.

Abstract

Researchers have long avoided neurophysiological experiments of overt speech production due to the suspicion that artifacts caused by muscle activity may lead to a bad signal-to-noise ratio in the measurements. However, the need to actually produce speech may influence earlier processing and qualitatively change speech production processes and what we can infer from neurophysiological measures thereof. Recently, however, overt speech has been successfully investigated using EEG, MEG, and fMRI. The aim of this Research Topic is to draw together recent research on the neurophysiological basis of language production, with the aim of developing and extending theoretical accounts of the language production process. In this Research Topic of Frontiers in Language Sciences, we invite both experimental and review papers, as well as those about the latest methods in acquisition and analysis of overt language production data. All aspects of language production are welcome: i.e., from conceptualization to articulation during native as well as multilingual language production. Focus should be placed on using the neurophysiological data to inform questions about the processing stages of language production. In addition, emphasis should be placed on the extent to which the identified components of the electrophysiological signal (e.g., ERP/ERF, neuronal oscillations, etc.), brain areas or networks are related to language comprehension and other cognitive domains. By bringing together electrophysiological and neuroimaging evidence on language production mechanisms, a more complete picture of the locus of language production processes and their temporal and neurophysiological signatures will emerge.

Abstract

Face to face interaction is fundamental to human sociality but is very complex to study in a scientific fashion. This theme issue brings together cutting-edge approaches to the study of face-to-face interaction and showcases how we can make progress in this area. Researchers are now studying interaction in adult conversation, parent-child relationships, neurodiverse groups, interactions with virtual agents and various animal species. The theme issue reveals how new paradigms are leading to more ecologically grounded and comprehensive insights into what social interaction is. Scientific advances in this area can lead to improvements in education and therapy, better understanding of neurodiversity and more engaging artificial agents

Abstract

Whitesands is an under-described language of southern Vanuatu, and this thesis presents Whitesands-specific data based on primary in-situ field research. The thesis addresses the distinction of noun and verb word classes in the language. It claims that current linguistic syntax theory cannot account for the argument structure of canonical object-denoting roots. It is shown that there are distinct lexical noun and verb classes in Whitesands but this is only a weak dichotomy. Stronger is the NP and VP distinction, and this is achieved by employing a new theoretical approach that proposes functional categories and their selection of complements as crucial tests of distinction. This approach contrasts with previous analyses of parts of speech in Oceanic languages and cross-linguistically. It ultimately explains many of the syntactic phenomena seen in the language family, including the above argument assignment dilemma, the alienable possession of nouns with classifiers and also the nominalisation processes.

Abstract

This special publication aims to build a renewed enthusiasm for collecting acquisition data across many languages, including those facing endangerment and loss. It presents a guide for documenting and describing child language and child-directed language in diverse languages and cultures, as well as a collection of acquisition sketches based on this guide. The guide is intended for anyone interested in working across child language and language documentation, including, for example, field linguists and language documenters, community language workers, child language researchers or graduate students.

Abstract

Baby's begrijpen woorden eerder dan dat ze deze zeggen. Dit stadium is onderbelicht want moeilijk waarneembaar. Caroline Junge onderzocht de vaardigheden die nodig zijn voor het leren van de eerste woordjes: conceptherkenning, woordherkenning en het verbinden van woord aan betekenis. Daarvoor bestudeerde ze de hersenpotentialen van het babybrein tijdens het horen van woordjes. Junge stelt vast dat baby's van negen maanden al woordbegrip hebben. En dat is veel vroeger dan tot nu toe bekend was. Als baby's een woord hoorde dat niet klopte met het plaatje dat ze zagen, lieten ze een N400-effect zien, een klassiek hersenpotentiaal. Uit eerder Duits onderzoek is gebleken dat baby's van twaalf maanden dit effect nog niet laten zien, omdat de hersenen nog niet rijp zouden zijn. Het onderzoek van Junge weerlegt dit. Ook laat ze zien dat als baby's goed woorden kunnen herkennen binnen zinnetjes, dit belangrijk is voor hun latere taalontwikkeling, wat mogelijk tot nieuwe therapieën voor taalstoornissen zal leiden.

Abstract

This dissertation investigates two seemingly contradictory properties of the speech perception system. On the one hand, listeners are extremely sensitive to the fine phonetic details in the speech signal. These subtle acoustic cues can reduce the temporal ambiguity between words that show initial segmental overlap, and can guide lexical activation. On the other hand, comprehension does not seem to be hampered at all by the drastic reductions that typically occur in casual speech. Complete segments, and sometimes even complete syllables, may be missing, but comprehension is seemingly unaffected. This thesis aims at elucidating how words are represented and accessed in the mental lexicon, by investigating these contradictory phenomena for the domain of morphology

Abstract

This thesis addressed the spoken production of complex numerals for time and space. The production of complex numerical expressions like those involved in telling time (e.g., 'quarter to four') or producing house numbers (e.g., 'two hundred forty-five') has been almost completely ignored. Yet, adult speakers produce such expressions on a regular basis in everyday communication. Thus, no theory on numerical cognition or speech production is complete without an account of the production of multi-morphemic utterances such as complex numeral expressions. The main question of this thesis is which particular speech planning levels are involved in the naming and reading of complex numerals for time and space. More specifically, this issue was investigated by examining different modes of response (clock times versus house numbers), alternative input formats (Arabic digit versus alphabetic format; analog versus digital clock displays), and different expression types (relative 'quarter to four' versus absolute 'three forty-five' time expressions).

Abstract

This thesis is about whether language affects thinking. It deals with the linguistic relativity hypothesis, which proposes that the language we speak influences the way we think. This hypothesis is investigated in the domain of caused motion (e.g., ‘The man rolled the tyre into the garage’), by looking at Spanish and Swedish, two languages that show striking differences in how motion events are encoded. The thesis consists of four studies. The first two focus on native speakers of Spanish and Swedish. Study I compares how Spanish and Swedish speakers describe the same set of caused motion events, directing the spotlight at how variable the descriptions are in each language. The results confirm earlier findings from semantic typology regarding the dominant ways of expressing the events in each language: Spanish behaves like a verb-framed language and Swedish like a satellite-framed language (Talmy, 2000). Going beyond previous findings, the study demonstrates—using the tools of entropy and Monte Carlo simulations—that there is markedly more variability in Spanish than in Swedish descriptions. Study II tests whether differences in how Spanish and Swedish speakers describe caused motion events are reflected in how they think about such events. Using a novel similarity arrangement task, it is found that Spanish and Swedish speakers partly differ in how they represent caused motion events if they can access language during the task. However, the differences disappear when the possibility to use language is momentarily blocked by an interference task. The last two studies focus on Swedish learners of Spanish as a second language (L2). Study III explores how Swedish learners (compared to native Spanish speakers) adapt their Spanish motion descriptions to recently encountered input. Using insights from the literature on structural priming, we find that Swedish learners initially expect to encounter in their L2, Spanish, those verb types that are typical in Swedish (manner verbs like ‘roll’) but that, with increasing proficiency, their expectations become increasingly attuned to the typical Spanish pattern of using path verbs (like ‘enter’). These expectations are reflected in the way L2 learners adapt their own production to the Spanish input. Study IV asks whether recent linguistic experience in an L2 can affect how L2 learners think about motion events. It is found that encountering motion descriptions in the L2 that emphasize different types of information (path or manner) leads L2 speakers to perceive similarity along different dimensions in a subsequent similarity arrangement task. Taken together, the thesis argues that the study of the relation between language and thought affords more valuable insights when not posed as an either-or question (i.e., does language affect thought or not?). In this spirit, the thesis contributes to the wider aim of investigating the conditions under which language does or does not affect thought and explores what the different outcomes tell us about language, thought, and the intricate mechanisms that relate them.

Abstract

Many Mayan languages make use of a special dependent verb form (the Agent Focus, or AF verb form), which alternates with the normal transitive verb form (the synthetic verb form) of main clauses when the subject of a transitive verb is focused, questioned or relativized. It has been a centerpiece of research in Mayan morphosyntax over the last forty years, due to its puzzling formal and distributional properties. In this dissertation I show how a usage-oriented approach to the phenomenon can provide important insights into this area of grammar which resists any categorical explanation. I propose that the historical origins of these special verb forms can be traced to the emergence of head marking. Drawing on cross-linguistic and historical data, I argue that the special verbs that occur in A-bar dependencies in Yucatec and a range of head-marking languages are byproducts of the frequency-sensitive gramaticalization process by which independent pronouns become pronominal inflection on verbs. I show that the relatively low frequency of adjacent pronoun-verb combinations in extraction contexts (where gaps are more frequent than resumptive pronouns) can give rise to asymmetric patterns of pronoun grammaticalization, and thus lead to the emergence of these morphological alternations. The asymmetric frequency distributions of gaps and RPs (within and across languages) in turn can be explained by processing preferences. I present three experiments which show that Yucatec speakers are more likely to use the resumptive verb form in embedded environments, and where the antecedent is indefinite. Specifically, these studies indicate the need to bring discourse-level processing principles into the account of what have often been taken to be autonomously sentence-internal phenomena: factors such as distance and the referential salience of the antecedent have been shown to influence referential form choice in discourse, suggesting that the same cognitive principles lie behind both types of variation. More generally, the Yucatec studies demonstrate that production preferences in Yucatec relative clauses reflect patterns of RP/gap distributions that have been attested across grammars. The Highest Subject Restriction (the ban on subject RPs in local dependencies), which is apparently a categorical constraint in many languages, is reflected probabilistically in Yucatec in terms of production preferences. The definiteness restriction (RPs are obligatory with indefinite antecedents), which has been reported categorically in other languages, is also visible probabilistically in Yucatec production. This lends some statistically robust support to the view that typological patterns can arise via the conventionalization of processing preferences.

Abstract

Typologies are critical tools for linguists, but typologies, like grammars, are known to leak. This book addresses the question of typological overlap from the perspective of a single language. In Lowland Chontal of Oaxaca, a language of southern Mexico, change events are expressed with three types of predicates, and each predicate type corresponds to a different language type in the well-known typology of lexicalization patterns established by Talmy and elaborated by others. O’Connor evaluates the predictive powers of the typology by examining the consequences of each predicate type in a variety of contexts, using data from narrative discourse, stimulus response, and elicitation. This is the first de­tailed look at the lexical and grammatical resources of the verbal system in Chontal and their relation to semantics of change. The analysis of how and why Chontal speakers choose among these verbal resources to achieve particular communicative and social goals serves both as a documentation of an endangered language and a theoretical contribution towards a typology of language use.

Abstract

Recent studies of wh-question acquisition have tended to come from the nativist side of the language acquisition debate with little input from a constructivist perspective. The present work was designed to redress the balance, first by presenting a detailed description of young children's wh-question acquisition data, second, by providing detailed critiques of two nativist theories of wh- question acquisition, and third, by presenting a preliminary account of young children's wh-question development from a constructivist perspective. Analyses of the data from twelve 2 to 3 year old children collected over a year and of data from an older child (Adam from the Brown corpus, 1973) are described and three conclusions are drawn. First it is argued that the data suggest that children's knowledge of how to form wh-questions builds up gradually as they learn how to combine lexical items such as wh-words and auxiliaries in specific ways. Second, it is concluded that two nativist theories of grammatical development (Radford, 1990, 1992, 1995, 1996, Valian, Lasser & Mandelbaum, 1992) fail to account successfully for the wh-question data produced by the children. Third, it is asserted that the lexically-specific nature of children's early wh-questions is compatible with a lexical constructivist view of development, which proposes that the language learning mechanism learns by picking up high frequency lexical patterns from the input. The implications of these conclusions for theories of language development and future research are discussed.

Abstract

Functional Magnetic Resonance Imaging (fMRI) and Electropencephalography (EEG) are the two techniques that are most often used to study the working brain. With the first technique we use the MRI machine to measure where in the brain the supply of oxygenated blood increases as result of an increased neural activity with a high precision. The temporal resolution of this measure however is limited to a few seconds. With EEG we measure the electrical activity of the brain with millisecond precision by placing electrodes on the skin of the head. We can think of the EEG signal as a signal that consists of multiple superimposed frequencies that vary their strength over time and when performing a cognitive task. Since we measure EEG at the level of the scalp, it is difficult to know where in the brain the signals exactly originate from. For about a decade we are able to measure fMRI and EEG at the same time, which possibly enables us to combine the superior spatial resolution of fMRI with the superior temporal resolution of EEG. To make this possible, we need to understand how the EEG signal is related to the fMRI signal, which is the central theme of this thesis. The main finding in this thesis is that increases in the strength of EEG frequencies below 30 Hz are related to a decrease in the fMRI signal strength, while increases in the strength of frequencies above 40 Hz is related to an increase in the strength of the fMRI signal. Changes in the strength of the low EEG frequencies are however are not coupled to changes in high frequencies. Changes in the strength of low and high EEG frequencies therefore contribute independently to changes in the fMRI signal.

Abstract

Sarah Schimke onderzocht hoe mensen die op volwassen leeftijd naar een ander land verhuizen de taal van dit land leren, ook zonder veel taalinstructie te krijgen. Twee groepen werden onderzocht: Turkse immigranten in Frankrijk en Turkse immigranten in Duitsland. De resultaten laten zien dat volwassen leerlingen in het begin van het verwervingsproces een gemakkelijkere variatie van de doeltaal creëren. Er worden wel woorden van de doeltaal verworven en gebruikt, maar er wordt een gesimplificeerde grammatica toegepast. In het bijzonder gebruiken leerlingen in deze fase geen finietheid, dus geen morfologische variaties van werkwoorden. Schimke toont aan dat als finietheid wordt verworven, dit de grammatica van de leerlingen sterk verandert en dat deze veel sterker op de doeltaalgrammatica begint te lijken. Ook toont ze aan dat dit proces door karakteristieken van de doeltaal, zoals de woordvolgorde en de complexiteit van de morfologie, wordt beïnvloed

Abstract

Op een gemiddelde dag luisteren mensen naar spraak van heel veel verschillende mensen. Die hebben allemaal een ander stemgeluid, waardoor de woorden die zij uitspreken verschillend klinken. Luisteraars hebben daar echter weinig hinder van. Hoe is het mogelijk dat luisteraars zich zo gemakkelijk kunnen aanpassen aan verschillende sprekers? Matthias Sjerps onderzocht in zijn proefschrift een cognitief mechanisme dat luisteraars helpt om zich aan te passen aan de karakteristieken van verschillende sprekers. Hierbij maakt een luisteraar gebruik van informatie in de context. Dit mechanisme blijkt vroeg in de spraakverwerking plaats te vinden. Bovendien beïnvloedt dit mechanisme ook de perceptie van andere geluiden dan spraak. Dit laat zien dat het een zeer breed en algemeen perceptueel mechanisme betreft. Contexteffecten bleken echter sterker voor spraakgeluiden dan voor andere geluiden. Dit suggereert dat het onderzochte mechanisme, ook al is het algemeen en breed toepasbaar, versterkt kan worden door blootstelling aan taal.

Abstract

Spraakklanken, lettergrepen en woorden worden vaak minder duidelijk uitgesproken in spontane conversaties dan in formelere spreekstijlen. Dit proefschrift presenteert onderzoek naar spraakreductie in spontaan Frans en Spaans. Naar deze talen is tot nu toe weinig spraakreductieonderzoek gedaan. Er worden twee nieuwe grote corpora met spontaan Frans en Spaans beschreven. Op basis van deze corpora heb ik enkele onderzoeken gedaan waarin ik de volgende belangrijke conclusies heb getrokken. Allereerst vond ik dat akoestische data van spontane spraak waardevolle informatie kan geven over de vraag of specifieke reductiefenomenen categoriaal of continu zijn. Verder vond ik, in tegenstelling tot onderzoek naar Germaanse talen, slechts gedeeltelijk bewijs dat spraakreductie in Romaanse talen als het Frans en het Spaans beïnvloed wordt door de eigenschappen en voorspelbaarheid van het woord. Ten derde vond ik door spontaan Frans en Spaans te vergelijken dat spraakreductie tussen talen meer kan verschillen dan je zou verwachten op basis van laboratoriumonderzoek