Publications

Abstract

In this dissertation the perceptual relevance of prevoicing in Dutch was investigated. Prevoicing is the presence of vocal fold vibration during the closure of initial voiced plosives (negative voice onset time). The presence or absence of prevoicing is generally used to describe the difference between voiced and voiceless Dutch plosives. The first experiment described in this dissertation showed that prevoicing is frequently absent in Dutch and that several factors affect the production of prevoicing. A detailed acoustic analysis of the voicing distinction identified several acoustic correlates of voicing. Prevoicing appeared to be by far the best predictor. Perceptual classification data revealed that prevoicing was indeed the strongest cue that listeners use when classifying plosives as voiced or voiceless. In the cases where prevoicing was absent, other acoustic cues influenced classification, such that some of these tokens were still perceived as being voiced. In the second part of this dissertation the influence of prevoicing variation on spoken-word recognition was examined. In several cross-modal priming experiments two types of prevoicing variation were contrasted: a difference between the presence and absence of prevoicing (6 versus 0 periods of prevoicing) and a difference in the amount of prevoicing (12 versus 6 periods). All these experiments indicated that primes with 12 and 6 periods of prevoicing had the same effect on lexical decisions to the visual targets. The primes without prevoicing had a different effect, but only when their voiceless counterparts were real words. Phonetic detail appears to influence lexical access only when it is useful: In Dutch, the presence versus absence of prevoicing is informative, while the amount of prevoicing is not.

Abstract

The aim of this thesis was to gain more insight into spoken-word comprehension and the influence of sentence-contextual information on these processes using ERPs. By manipulating critical words in semantically constraining sententes, in semantic or syntactic sense, and examining the consequences in the electrophysiological signal (e.g., elicitation of ERP components such as the N400, N200, LAN, and P600), three questions were tackled: I At which moment is context information used in the spoken-word recognition process? II What is the temporal relationship between lexical selection and integration of the meaning of a spoken word into a higher-order level representeation of the preceding sentence? III What is the time course of the processing of different sources of linguistic information obtained from the context, such as phonological, semantic and syntactic information, during spoken-word comprehension? From the results of this thesis it can be concluded that sentential context already exerts an influence on spoken-word processing at approximately 200 ms after word onset. In addition, semantic integration is attempted before a spoken word can be selected on the basis of the acoustic signal, i.e. before lexical selection is completed. Finally, knowledge of the syntactic category of a word is not needed before semantic integration can take place. These findings, therefore, were interpreted as providing evidence for an account of cascaded spoken-word processing that proclaims an optimal use of contextual information during spoken-word identification. Optimal use is accomplished by allowing for semantic and syntactic processing to take place in parallel after bottom-up activation of a set of candidates, and lexical integration to proceed with a limited number of candidates that still match the acoustic input

Abstract

In a small village in the north of Bali called Bengkala, relatively many people inherit deafness. The Balinese therefore refer to this village as Desa Kolok, which means 'deaf village'. Connie de Vos studied Kata Kolok, the sign language of this village, and the ways in which the language recruits space to talk about both spatial and non-spatial matters. he small village community Bengkala in the north of Bali has almost 3,000 inhabitants. Of all the inhabitants, 57% use sign language, with varying degrees of fluency. But of this signing community (between 1,200 and 1,800 signers, depending on your definition of 'signer'), only 4% are deaf. So, not only do the deaf people of Bengkala use the sign language Kata Kolok, but also the majority of the hearing population.
"I've worked with deaf people from all over Asia, Europe, and also some signers in America," says Connie de Vos of MPI's Language and Cognition Department, and Centre for Language Studies (RU). "What sets apart this particular deaf village is that deaf individuals are highly integrated within the village clans. There is really a huge proportion of hearing signers." The sign language currently functions in all major aspects of village life and has been acquired from birth by multiple generations of deaf, native signers. According to De Vos, Kata Kolok is a fully-fledged sign language in every sense of the word. As a collaborative project, she has initiated inclusive deaf education within the village and now Kata Kolok is used as the primary language of instruction. De Vos' primary finding is that Kata Kolok discourse uses a different system of referring to space than other sign languages. Spatial relations are represented by a so-called "absolute frame of reference", based on geographic locations and wind directions. "All sign languages, as we know, use relative constructions for spatial relations. They use signs comparable to words like 'left' and 'right' instead of 'east' and 'west'. Kata Kolok does the latter. Kata Kolok signers appear to have an internal compass to continually register their position in space."De Vos is the first sign linguist who has documented Kata Kolok extensively. She spent more than a year in the village and collected over a hundred hours of video material of spontaneous conversations. "One of the things I've noticed is that language doesn't really emerge out of nothing," she says. "Signers adopt a local gesture system and transform it into a new and much more systematic sign language. A lot of the signs refer to concepts they're familiar with. That's why hearing signers have no difficulties in picking up Kata Kolok. Kata Kolok unites the hearing and the deaf.

Abstract

Many people speak a second language next to their mother tongue. How do they learn this language and how does the brain process it compared to the native language? A second language can be learned without explicit instruction. Our brains automatically pick up grammatical structures, such as word order, when these structures are repeated frequently during learning. The learning takes place within hours or days and the same brain areas, such as frontal and temporal brain regions, that process our native language are very quickly activated. When people master a second language very well, even the same neuronal populations in these language brain areas are involved. This is especially the case when the grammatical structures are similar. In conclusion, it appears that a second language builds on the existing cognitive and neural mechanisms of the native language as much as possible.

Abstract

In recent decades, neuroimaging studies on the neural infrastructure of language are usually (or mostly) conducted with certain on-line language processing tasks. These functional neuroimaging studies helped to localize the language areas in the brain and to investigate the brain activity during explicit language processing. However, little is known about what is going on with the language areas when the brain is ‘at rest’, i.e., when there is no explicit language processing running. Taking advantage of the fcMRI and DTI techniques, this thesis is able to investigate the language function ‘off-line’ at the neuronal network level and the connectivity among language areas in the brain. Based on patient studies, the traditional, classical model on the perisylvian language network specifies a “Broca’ area – Arcuate Fasciculus – Werinicke’s area” loop (Ojemann 1991). With the help of modern neuroimaging techniques, researchers have been able to track language pathways that involve more brain structures than are in the classical model, and relate them to certain language functions. In such a background, a large part of this thesis made a contribution to the study of the topology of the language networks. It revealed that the language networks form a topographical functional connectivity pattern in the left hemisphere for the right-handers. This thesis also revealed the importance of structural hubs, such as Broca’s and Wernicke’s areas, which have more connectivity to other brain areas and play a central role in the language networks. Furthermore, this thesis revealed both functionally and structurally lateralized language networks in the brain. The consistency between what is found in this thesis and what has been known from previous functional studies seems to suggest, that the human brain is optimized and ‘ready’ for the language function even when there is currently no explicit language-processing running.