Publications

Abstract

Between 2 and 5% of children who are otherwise unimpaired have significant difficulties in acquiring expressive and/or receptive language, despite adequate intelligence and opportunity. While twin studies indicate a significant role for genetic factors in developmental disorders of speech and language, the majority of families segregating such disorders show complex patterns of inheritance, and are thus not amenable for conventional linkage analysis. A rare exception is the KE family, a large three-generation pedigree in which approximately half of the members are affected with a severe speech and language disorder which appears to be transmitted as an autosomal dominant monogenic trait. This family has been widely publicised as suffering primarily from a defect in the use of grammatical suffixation rules, thus supposedly supporting the existence of genes specific to grammar. The phenotype, however, is broader in nature, with virtually every aspect of grammar and of language affected. In addition, affected members have a severe orofacial dyspraxia, and their speech is largely incomprehensible to the naive listener. We initiated a genome-wide search for linkage in the KE family and have identified a region on chromosome 7 which co-segregates with the speech and language disorder (maximum lod score = 6.62 at theta = 0.0), confirming autosomal dominant inheritance with full penetrance. Further analysis of microsatellites from within the region enabled us to fine map the locus responsible (designated SPCH1) to a 5.6-cM interval in 7q31, thus providing an important step towards its identification. Isolation of SPCH1 may offer the first insight into the molecular genetics of the developmental process that culminates in speech and language.

Abstract

The human Xp11.23-p11.22 interval has been implicated in several inherited diseases including Wiskott-Aldrich syndrome; three forms of X-linked hypercalciuric nephrolithiaisis; and the eye disorders retinitis pigmentosa 2, congenital stationary night blindness, and Aland Island eye disease. In constructing YAC contigs spanning Xp11. 23-p11.22, we have previously shown that the region around the synaptophysin (SYP) gene is refractory to cloning in YACs, but highly stable in cosmids. Preliminary analysis of the latter suggested that this might reflect a high density of coding sequences and we therefore undertook the complete sequencing of a SYP-containing cosmid. Sequence data were extensively analyzed using computer programs such as CENSOR (to mask repeats), BLAST (for homology searches), and GRAIL and GENE-ID (to predict exons). This revealed the presence of 29 putative exons, organized into three genes, in addition to the 7 exons of the complete SYP coding region, all mapping within a 44-kb interval. Two genes are novel, one (CACNA1F) showing high homology to alpha1 subunits of calcium channels, the other (LMO6) encoding a product with significant similarity to LIM-domain proteins. RT-PCR and Northern blot studies confirmed that these loci are indeed transcribed. The third locus is the previously described, but not previously localized, A4 differentiation-dependent gene. Given that the intron-exon boundaries predicted by the analysis are consistent with previous information where available, we have been able to suggest the genomic organization of the novel genes with some confidence. The region has an elevated GC content (>53%), and we identified CpG islands associated with the 5' ends of SYP, A4, and LMO6. The order of loci was Xpter-A4-LMO6-SYP-CACNA1F-Xcen, with intergenic distances ranging from approximately 300 bp to approximately 5 kb. The density of transcribed sequences in this area (>80%) is comparable to that found in the highly gene-rich chromosomal band Xq28. Further studies may aid our understanding of the long-range organization surrounding such gene-enriched regions.

Abstract

Reaction time to detect a phoneme target in a sentence was found to be faster when the word in which the target occurred formed part of the semantic focus of the sentence. Focus was determined by asking a question before the sentence; that part of the sentence which comprised the answer to the sentence was assumed to be focussed. This procedure made it possible to vary position offocus within the sentence while holding all acoustic aspects of the sentence itself constant. It is argued that sentence understanding is facilitated by rapid identification of focussed information. Since focussed words are usually accented, it is further argued that the active search for accented words demonstrated in previous research should be interpreted as a search for semantic focus.

Abstract

This research exploits the English and Dutch CELEX lexical database to investigate the form similarity relations between words. Lexical statistics analyses replicate and extend the findings of Landauer and Streeter (1973) concerning the relation between a word′s frequency and the density and frequency of its similarity neighborhood. The results for both Dutch and English reveal only a weak tendency for high-frequency written and spoken words to have more neighbors than rare words and for these neighbors to be more frequent than those of rare words. However, the number of neighbors was found to correlate more highly with bigram frequency than with word frequency. To clarify the relations between these properties, a stochastic model is presented which captures the relevant effects of phonotactic structure on neighborhood similarities. The implications of these findings for models of language production and comprehension are considered.

Abstract

A key function of attention is to select an appropriate subset of available information by facilitation of attended processes and/or inhibition of irrelevant processing. Functional imaging studies, using positron emission tomography, have during different experimental tasks revealed decreased neuronal activity in areas that process input from unattended sensory modalities. It has been hypothesized that these decreases reflect a selective inhibitory modulation of nonrelevant cortical processing. In this study we addressed this question using a continuous arithmetical task with and without concomitant disturbing auditory input (task-irrelevant speech). During the arithmetical task, irrelevant speech did not affect task-performance but yielded decreased activity in the auditory and midcingulate cortices and increased activity in the left posterior parietal cortex. This pattern of modulation is consistent with a top down inhibitory modulation of a nonattended input to the auditory cortex and a coexisting, attention-based facilitation of taskrelevant processing in higher order cortices. These findings suggest that task-related decreases in cortical activity may be of functional importance in the understanding of both attentional mechanisms and taskrelated information processing.

Abstract

Gestures are often regarded as the most typical compensatory device used by language learners in communicative trouble. Yet gestural solutions to communicative problems have rarely been studied within any theory of second language use. The work pre­sented in this volume aims to account for second language learners’ strategic use of speech-associated gestures by combining a process-oriented framework for communi­cation strategies with a cognitive theory of gesture. Two empirical studies are presented. The production study investigates Swedish lear­ners of French and French learners of Swedish and their use of strategic gestures. The results, which are based on analyses of both individual and group behaviour, contradict popular opinion as well as theoretical assumptions from both fields. Gestures are not primarily used to replace speech, nor are they chiefly mimetic. Instead, learners use gestures with speech, and although they do exploit mimetic gestures to solve lexical problems, they also use more abstract gestures to handle discourse-related difficulties and metalinguistic commentary. The influence of factors such as proficiency, task, culture, and strategic competence on gesture use is discussed, and the oral and gestural strategic modes are compared. In the evaluation study, native speakers’ assessments of learners’ gestures, and the potential effect of gestures on evaluations of proficiency are analysed and discussed in terms of individual communicative style. Compensatory gestures function at multiple communicative levels. This has implica­tions for theories of communication strategies, and an expansion of the existing frameworks is discussed taking both cognitive and interactive aspects into account.

Abstract

Broca′s and Wernicke′s aphasics performed speeded lexical decisions on the third member of auditorily presented triplets consisting of two word primes followed by either a word or a nonword. In three of the four priming conditions, the second prime was a homonym with two unrelated meanings. The relation of the first prime and the target with the two meanings of the homonym was manipulated in the different priming conditions. The two readings of the ambiguous words either shared their grammatical form class (noun-noun ambiguities) or not (noun-verb ambiguities). The silent intervals between the members of the triplets were varied between 100, 500, and 1250 msec. Priming at the shortest interval is mainly attributed to automatic lexical processing, and priming at the longest interval is mainly due to forms of controlled lexical processing. For both Broca′s and Wernicke′s aphasics overall priming effects were obtained at ISIs of 100 and 500 msec, but not at an ISI of 1250 msec. This pattern of results is consistent with the view that both types of aphasics can automatically access the semantic lexicon, but might be impaired in integrating lexical-semantic information into the context. Broca′s aphasics showed a specific impairment in selecting the contextually appropriate reading of noun-verb ambiguities, which is suggested to result from a failure either in the on-line morphological parsing of complex word forms into a stem and an inflection or in the on-line exploitation of the syntactic implications of the inflectional suffix. In a final experiment patients were asked to explicitly judge the semantic relations between a subset of the primes that were used in the lexical decision study. Wernicke′s aphasics performed worse than both Broca′s aphasics and normal controls, indicating a specific impairment for these patients in consciously operating on automatically accessed lexical-semantic information.

Abstract

This study tests the recent claim that Broca’s aphasics are impaired in automatic lexical access, including the retrieval of word meaning. Subjects are required to perform a lexical decision on visually presented prime target pairs. Half of the word targets are preceded by a related word, half by an unrelated word. Primes and targets are presented with a long stimulus-onset-asynchrony (SOA) of 1400 msec and with a short SOA of 300 msec. Normal priming effects are observed in Broca’s aphasics for both SOAs. This result is discussed in the context of the claim that Broca’s aphasics suffer from an impairment in the automatic access of lexical–semantic information. It is argued that none of the current priming studies provides evidence supporting this claim, since with short SOAs priming effects have been reliably obtained in Broca’s aphasics. The results are more compatible with the claim that in many Broca’s aphasics the functional locus of their comprehension deficit is at the level of postlexical integration processes.

Abstract

This paper presents event-related brain potential (ERP) data from an experiment on syntactic processing. Subjects read individual sentences containing one of three different kinds of violations of the syntactic constraints of Dutch. The ERP results provide evidence for M electrophysiological response to syntactic processing that is qualitatively different from established ERP responses to semantic processing. We refer to this electro-physiological manifestation of parsing as the Syntactic Positive Shift (SPS). The SPS was observed in an experiment in which no task demands, other than to read the input, were imposed on the subjects. The pattern of responses to the different kinds of syntactic violations suggests that the SPS indicates the impossibility for the parser to assign the preferred structure to an incoming string of words, irrespective of the specific syntactic nature of this preferred structure. The implications of these findings for further research on parsing are discussed.

Abstract

Stimulus-related changes in cerebral blood oxygenation were measured using high-resolution functional magnetic resonance imaging sequentially covering visual occipital areas in contiguous sections. During dynamic imaging, healthy subjects silently viewed pseudowords, single false fonts, or length-matched strings of the same false fonts. The paradigm consisted of a sixfold alternation of an activation and a control task. With pseudowords as activation vs single false fonts as control, responses were seen mainly in medial occipital cortex. These responses disappeared when pseudowords were alternated with false font strings as the control and reappeared when false font strings instead of pseudowords served as activation and were alternated with single false fonts. The string-length contrast alone, therefore, is sufficient to account for the activation pattern observed in medial visual cortex when word-like stimuli are contrasted with single characters.

Abstract

The aim of this paper is to discuss an inherent difficulty of PET (and fMRI) research in language production. On the one hand, language production presupposes some degree of freedom for the subject, on the other hand, interpretability of results presupposes restrictions of this freedom. This difficulty is reflected in the existing PET literature in some neglect of the general principle to design experiments in such a way that the results do not allow for alternative interpretations. It is argued that by narrowing down the scope of experiments a gain in interpretability can be achieved.

Abstract

One critical aspect of language acquisition is the development of a lexicon that associates sounds and meanings; but developing a lexicon first requires that the infant segment utterances into individual words. How might the infant begin this process? The present study was designed to examine the potential role that sensitivity to predominant stress patterns of words might play in lexical development. In English, by far the majority of words have stressed (strong) initial syllables. Experiment 1 of our study demonstrated that by 9 months of age American infants listen significantly longer to words with strong/weak stress patterns than to words with weak/strong stress patterns. However, Experiment 2 showed that no significant preferences for the predominant stress pattern appear with 6-month-old infants, which suggests that the preference develops as a result of increasing familiarity with the prosodic features of the native language. In a third experiment, 9-month-olds showed a preference for strong/weak patterns even when the speech input was low-pass filtered, which suggests that their preference is specifically for the prosodic structure of the words. Together the results suggest that attention to predominant stress patterns in the native language may form an important part of the infant's process of developing a lexicon.

Abstract

When you compare the behavior of two different age groups which are trying to master the same sensori-motor or cognitive skill, you are likely to discover varying learning routes: different stages, different intervals between stages, or even different orderings of stages. Such heterogeneous learning trajectories may be caused by at least six different types of factors: (1) Initial state: the kinds and levels of skills the learners have available at the onset of the learning episode. (2) Learning mechanisms: rule-based, inductive, connectionist, parameter setting, and so on. (3) Input and feedback characteristics: learning stimuli, information about success and failure. (4) Information processing mechanisms: capacity limitations, attentional biases, response preferences. (5) Energetic variables: motivation, emotional reactions. (6) Final state: the fine-structure of kinds and levels of subskills at the end of the learning episode. This applies to language acquisition as well. First and second language learners probably differ on all six factors. Nevertheless, the debate between advocates and opponents of the Fundamental Difference Hypothesis concerning L1 and L2 acquisition have looked almost exclusively at the first two factors. Those who believe that L1 learners have access to Universal Grammar whereas L2 learners rely on language processing strategies, postulate different learning mechanisms (UG parameter setting in L1, more general inductive strategies in L2 learning). Pienemann opposes this view and, based on his Processability Theory, argues that L1 and L2 learners start out from different initial states: they come to the grammar learning task with different structural hypotheses (SOV versus SVO as basic word order of German).

Abstract

[Seven one-page psycholinguistic sketches]

Abstract

Two experimental results often reported in support of perceptual interpretations concerning the influence of set on perception are critically examined: (a) the relation between word frequency and recognition threshold, and (b) the so-called compromise reactions between set and stimulus, Alter elimination of certain methodological artifacts (e.g., introduction of a temporal forced-choice method instead of the ascending-limits method), both phenomena disappear; the influence of set on perception appears to be wholly a matter of response bias.

Abstract

The previous literature has suggested that the hand movement in co-speech gestures and signs consists of a series of phases with qualitatively different dynamic characteristics. In this paper, we propose a syntagmatic rule system for movement phases that applies to both co-speech gestures and signs. Descriptive criteria for the rule system were developed for the analysis video-recorded continuous production of signs and gesture. It involves segmenting a stream of body movement into phases and identifying different phase types. Two human coders used the criteria to analyze signs and cospeech gestures that are produced in natural discourse. It was found that the criteria yielded good inter-coder reliability. These criteria can be used for the technology of automatic recognition of signs and co-speech gestures in order to segment continuous production and identify the potentially meaningbearing phase.

Abstract

Nobel's legacy, or the metamorphosis of what is idealistic Ever since the first Nobel prize in literature was awarded to Prudhomme in 1901, the decisions of the Swedish Academy have been subject to criticism. What is surprising in the changing decision policy as well as in its criticism is the fact that Alfred Nobel's original intentions are hardly ever taken into account: the Nobel prize is a philanthropic prize, it is not meant to select and honour the most eminent literary work but the work with maximal benefit to human beings. What is even more surprising is the fact that no one seems to care that the donator's Last Will is regularly broken.

Abstract

In this article, we discuss the implications of the fact that adult second language learners (outside the classroom) universally develop a well-structured, efficient and simple form of language–the Basic Variety (BV). Three questions are asked as to (1) the structural properties of the BV, (2) the status of these properties and (3) why some structural properties of ‘fully fledged’ languages are more complex. First, we characterize the BV in four respects: its lexical repertoire, the principles according to which utterances are structured, and temporality and spatiality expressed. The organizational principles proposed are small in number, and interact. We analyse this interaction, describing how the BV is put to use in various complex verbal tasks, in order to establish both what its communicative potentialities are, and also those discourse contexts where the constraints come into conflict and where the variety breaks down. This latter phenomenon provides a partial answer to the third question,concerning the relative complexity of ‘fully fledged’ languages–they have devices to deal with such cases. As for the second question, it is argued firstly that the empirically established continuity of the adult acquisition process precludes any assignment of the BV to a mode of linguistic expression (e.g., ‘protolanguage’) distinct from that of ‘fully fledged’ languages and, moreover, that the organizational constraints of the BV belong to the core attributes of the human language capacity, whereas a number of complexifications not attested in the BV are less central properties of this capacity. Finally, it is shown that the notion of feature strength, as used in recent versions of Generative Grammar, allows a straightforward characterization of the BV as a special case of an I-language, in the sense of this theory. Under this perspective, the acquisition of an Ilanguage beyond the BV can essentially be described as a change in feature strength.

Abstract

During the last 25 years, second language acquisition (SLA) research hasmade considerable progress, but is still far from proving a solid basis for foreign language teaching, or from a general theory of SLA. In addition, its status within the linguistic disciplines is still very low. I argue this has not much to do with low empirical or theoretical standards in the field—in this regard, SLA research is fully competitive—but with a particular perspective on the acquisition process: SLA researches learners' utterances as deviations from a certain target, instead of genuine manifestations of underlying language capacity; it analyses them in terms of what they are not rather than what they are. For some purposes such a "target deviation perspective" makes sense, but it will not help SLA researchers to substantially and independently contribute to a deeper understanding of the structure and function of the human language faculty. Therefore, these findings will remain of limited interest to other scientists until SLA researchers consider learner varieties a normal, in fact typical, manifestation of this unique human capacity.