Publications

Abstract

In the current paper, we asked at what level in the speech planning process speakers retrieve stored syllables. There is evidence that syllable structure plays an essential role in the phonological encoding of words (e.g., online syllabification and phonological word formation). There is also evidence that syllables are retrieved as whole units. However, findings that clearly pinpoint these effects to specific levels in speech planning are scarce. We used a naming variant of the implicit priming paradigm to contrast voice onset latencies for frequency-manipulated disyllabic Dutch pseudo-words. While prior implicit priming studies only manipulated the item's form and/or syllable structure overlap we introduced syllable frequency as an additional factor. If the preparation effect for syllables obtained in the implicit priming paradigm proceeds beyond phonological planning, i.e., includes the retrieval of stored syllables, then the preparation effect should differ for high- and low frequency syllables. The findings reported here confirm this prediction: Low-frequency syllables benefit significantly more from the preparation than high-frequency syllables. Our findings support the notion of a mental syllabary at a post-lexical level, between the levels of phonological and phonetic encoding.

Abstract

How does intention to speak become the action of speaking? It involves the generation of a preverbal message that is tailored to the requirements of a particular language, and through a series of steps, the message is transformed into a linear sequence of speech sounds (1, 2). These steps include retrieving different kinds of information from memory (semantic, syntactic, and phonological), and combining them into larger structures, a process called unification. Despite general agreement about the steps that connect intention to articulation, there is no consensus about their temporal profile or the role of feedback from later steps (3, 4). In addition, since the discovery by the French physician Pierre Paul Broca (in 1865) of the role of the left inferior frontal cortex in speaking, relatively little progress has been made in understanding the neural infrastructure that supports speech production (5). One reason is that the characteristics of natural language are uniquely human, and thus the neurobiology of language lacks an adequate animal model. But on page 445 of this issue, Sahin et al. (6) demonstrate, by recording neuronal activity in the human brain, that different kinds of linguistic information are indeed sequentially processed within Broca's area.

Abstract

In recent decades, psychologists have become increasingly interested in our ability to speak. This paper sketches the present theoretical perspective on this most complex skill of homo sapiens. The generation of fluent speech is based on the interaction of various processing components. These mechanisms are highly specialized, dedicated to performing specific subroutines, such as retrieving appropriate words, generating morpho-syntactic structure, computing the phonological target shape of syllables, words, phrases and whole utterances, and creating and executing articulatory programmes. As in any complex skill, there is a self-monitoring mechanism that checks the output. These component processes are targets of increasingly sophisticated experimental research, of which this paper presents a few salient examples.

Abstract

Three experiments examined the time course of phonological encoding in speech production. A new methodology is introduced in which subjects are required to monitor their internal speech production for prespecified target segments and syllables. Experiment 1 demonstrated that word initial target segments are monitored significantly faster than second syllable initial target segments. The addition of a concurrent articulation task (Experiment 1b) had a limited effect on performance, excluding the possibility that subjects are monitoring a subvocal articulation of the carrier word. Moreover, no relationship was observed between the pattern of monitoring latencies and the timing of the targets in subjects′ overt speech. Subjects are not, therefore, monitoring an internal phonetic representation of the carrier word. Experiment 2 used the production monitoring task to replicate the syllable monitoring effect observed in speech perception experiments: responses to targets were faster when they corresponded to the initial syllable of the carrier word than when they did not. We conclude that subjects are monitoring their internal generation of a syllabified phonological representation. Experiment 3 provides more detailed evidence concerning the time course of the generation of this representation by comparing monitoring latencies to targets within, as well as between, syllables. Some amendments to current models of phonological encoding are suggested in light of these results.

Abstract

PHD thesis, defended at the University of Leiden

Abstract

Firstly, theories are reviewed on the explanation of tonal consonance as the singular nature of tone intervals with frequency ratios corresponding with small integer numbers. An evaluation of these explanations in the light of some experimental studies supports the hypothesis, as promoted by von Helmholtz, that the difference between consonant and dissonant intervals is related to beats of adjacent partials. This relation was studied more fully by experiments in which subjects had to judge simple-tone intervals as a function of test frequency and interval width. The results may be considered as a modification of von Helmholtz's conception and indicate that, as a function of frequency, the transition range between consonant and dissonant intervals is related to critical bandwidth. Simple-tone intervals are evaluated as consonant for frequency differences exceeding this bandwidth. whereas the most dissonant intervals correspond with frequency differences of about a quarter of this bandwidth. On the base of these results, some properties of consonant intervals consisting of complex tones are explained. To answer the question whether critical bandwidth also plays a rôle in music, the chords of two compositions (parts of a trio sonata of J. S. Bach and of a string quartet of A. Dvorák) were analyzed by computing interval distributions as a function of frequency and number of harmonics taken into account. The results strongly suggest that, indeed, critical bandwidth plays an important rôle in music: for a number of harmonics representative for musical instruments, the "density" of simultaneous partials alters as a function of frequency in the same way as critical bandwidth does.