Publications

Abstract

Background

Forced switching between languages poses demands on control abilities, which may be difficult to meet for bilinguals with aphasia. Freely choosing languages has been shown to increase naming efficiency in healthy bilinguals, and lexical accessibility was found to be a predictor for language choice. The overlap between bilingual language switching and other types of switching is yet unclear.

Aims

This study aimed to examine the benefits of free language choice for bilinguals with aphasia and to investigate the overlap of between- and within-language switching abilities.

Methods & Procedures

Seventeen bilinguals with aphasia completed a questionnaire and four web-based picture naming tasks: single-language naming in the first and second language separately; voluntary switching between languages; cued and predictable switching between languages; cued and predictable switching between phrase types in the first language. Accuracy and naming latencies were analysed using (generalised) linear mixed-effects models.

Outcomes & Results

The results showed higher accuracy and faster naming for the voluntary switching condition compared to single-language naming and cued switching. Both voluntary and cued language switching yielded switch costs, and voluntary switch costs were larger. Ease of lexical access was a reliable predictor for voluntary language choice. We obtained no statistical evidence for differences or associations between switch costs in between- and within-language switching.

Conclusions

Several results point to benefits of voluntary language switching for bilinguals with aphasia. Freely mixing languages improved naming accuracy and speed, and ease of lexical access affected language choice. There was no statistical evidence for overlap of between- and within-language switching abilities. This study highlights the benefits of free language choice for bilinguals with aphasia.

Abstract

Previous research examining the factors that determine language choice and voluntary switching mainly involved early bilinguals. Here, using picture naming, we investigated language choice and switching in late Dutch–English bilinguals. We found that naming was overall slower in cued than in voluntary switching, but switch costs occurred in both types of switching. The magnitude of switch costs differed depending on the task and language, and was moderated by L2 proficiency. Self-rated rather than objectively assessed proficiency predicted voluntary switching and ease of lexical access was associated with language choice. Between-language and within-language switch costs were not correlated. These results highlight self-rated proficiency as a reliable predictor of voluntary switching, with language modulating switch costs. As in early bilinguals, ease of lexical access was related to word-level language choice of late bilinguals.

Abstract

On the basis of evidence from studies of the naming and reading of numerals, Ferrand (1999) argued that the naming of objects is slower than reading their names, due to a greater response uncertainty in naming than in reading, rather than to an obligatory conceptual preparation for naming, but not for reading. We manipulated the need for conceptual preparation, while keeping response uncertainty constant in the naming and reading of complex numerals. In Experiment 1, participants named three-digit Arabic numerals either as house numbers or clock times. House number naming latencies were determined mostly by morphophonological factors, such as morpheme frequency and the number of phonemes, whereas clock time naming latencies revealed an additional conceptual involvement. In Experiment 2, the numerals were presented in alphabetic format and had to be read aloud. Reading latencies were determined mostly by morphophonological factors in both modes. These results suggest that conceptual preparation, rather than response uncertainty, is responsible for the difference between naming and reading latencies.

Abstract

According to Levelt, Roelofs, and Meyer (1999) speakers generate the phonological and phonetic representations of successive syllables of a word in sequence and only begin to speak after having fully planned at least one complete phonological word. Therefore, speech onset latencies should be longer for long than for short words. We tested this prediction in four experiments in which Dutch participants named or categorized objects with monosyllabic or disyllabic names. Experiment 1 yielded a length effect on production latencies when objects with long and short names were tested in separate blocks, but not when they were mixed. Experiment 2 showed that the length effect was not due to a difference in the ease of object recognition. Experiment 3 replicated the results of Experiment 1 using a within-participants design. In Experiment 4, the long and short target words appeared in a phrasal context. In addition to the speech onset latencies, we obtained the viewing times for the target objects, which have been shown to depend on the time necessary to plan the form of the target names. We found word length effects for both dependent variables, but only when objects with short and long names were presented in separate blocks. We argue that in pure and mixed blocks speakers used different response deadlines, which they tried to meet by either generating the motor programs for one syllable or for all syllables of the word before speech onset. Computer simulations using WEAVER++ support this view.

Abstract

Four form-preparation experiments investigated whether aspects of phonological encoding processes and representations are shared between languages in bilingual speakers. The participants were Dutch--English bilinguals. Experiment 1 showed that the basic rightward incrementality revealed in studies for the first language is also observed for second-language words. In Experiments 2 and 3, speakers were given words to produce that did or did not share onset segments, and that came or did not come from different languages. It was found that when onsets were shared among the response words, those onsets were prepared, even when the words came from different languages. Experiment 4 showed that preparation requires prior knowledge of the segments and that knowledge about their phonological features yields no effect. These results suggest that both first- and second-language words are phonologically planned through the same serial order mechanism and that the representations of segments common to the languages are shared.

Abstract

This article presents a new account of the color-word Stroop phenomenon ( J. R. Stroop, 1935) based on an implemented model of word production, WEAVER++ ( W. J. M. Levelt, A. Roelofs, & A. S. Meyer, 1999b; A. Roelofs, 1992, 1997c). Stroop effects are claimed to arise from processing interactions within the language-production architecture and explicit goal-referenced control. WEAVER++ successfully simulates 16 classic data sets, mostly taken from the review by C. M. MacLeod (1991), including incongruency, congruency, reverse-Stroop, response-set, semantic-gradient, time-course, stimulus, spatial, multiple-task, manual, bilingual, training, age, and pathological effects. Three new experiments tested the account against alternative explanations. It is shown that WEAVER++ offers a more satisfactory account of the data than other models.

Abstract

The authors report six implicit priming experiments that examined the production of inflected forms. Participants produced words out of small sets in response to prompts. The words differed in form or shared word-initial segments, which allowed for preparation. In constant inflectional sets, the words had the same number of inflectional suffixes, whereas in variable sets the number of suffixes differed. In the experiments, preparation effects were obtained, which were larger in the constant than in the variable sets. Control experiments showed that this difference in effect was not due to syntactic class or phonological form per se. The results are interpreted in terms of a slot-and-filler model of word production, in which inflectional frames, on the one hand, and stems and affixes, on the other hand, are independently spelled out on the basis of an abstract morpho-syntactic specification of the word, which is followed by morpheme-to-frame association.

Abstract

Santiago, MacKay, Palma, and Rho (2000) report two picture naming experiments examining the role of syllable onset complexity and number of syllables in spoken word production. Experiment 1 showed that naming latencies are longer for words with two syllables (e.g., demon ) than one syllable (e.g., duck ), and longer for words beginning with a consonant cluster (e.g., drill ) than a single consonant (e.g., duck ). Experiment 2 replicated these findings and showed that the complexity of the syllable nucleus and coda has no effect. These results are taken to support MacKay's (1987) Node Structure theory and to refute models such as WEAVER++ (Roelofs, 1997a) that predict effects of word length but not of onset complexity and number of syllables per se. In this comment, I show that a re-analysis of the data of Santiago et al. that takes word length into account leads to the opposite conclusion. The observed effects of onset complexity and number of syllables appear to be length effects, supporting WEAVER++ and contradicting the Node Structure theory.

Abstract

Minimalist theories of spoken language planning hold that articulation starts when the first
speech segment has been planned, whereas non-minimalist theories assume larger units (e.g.,
Levelt, Roelofs, & Meyer, 1999a). Three experiments are reported, which were designed to distinguish
between these views using a newhybrid task that factorially manipulated preparation and
auditory priming of spoken language production. Minimalist theories predict no effect from
priming of non-initial segments when the initial segment of an utterance is already prepared;
observing such a priming effect would support non-minimalist theories. In all three experiments,
preparation and priming yielded main effects, and together their effects were additive. Preparation
of initial segments does not eliminate priming effects for later segments. These results challenge
the minimalist view. The findings are simulated by WEAVER++ (Roelofs, 1997b), which
employs the phonological word as the lower limit for articulation initiation.

Abstract

The control of language use has in its simplest form perhaps been most intensively studied using the color–word Stroop task. The authors review chronometric and neuroimaging evidence on Stroop task performance to evaluate two prominent, implemented models of control in naming and reading: GRAIN and WEAVER++. Computer simulations are reported, which reveal that WEAVER++ offers a more satisfactory account of the data than GRAIN. In particular, we report WEAVER++ simulations of the BOLD response in anterior cingulate cortex during Stroop performance. Aspects of single-word production and perception in the Stroop task are discussed in relation to the wider problem of the control of language use.

Abstract

The authors report a study in Dutch that used an on-line preparation paradigm to test the issue of semantic
dependency versus morphological autonomy in the production of polymorphemic words. Semantically
transparent complex words (like input in English) and semantically opaque complex words
(like invoice) showed clear evidence of morphological structure in word-form encoding, since both exhibited
an equally large preparation effect that was much greater than that for morphologically simple
words (like insect). These results suggest that morphemes may be planning units in the production of
complex words, without making a semantic contribution, thereby supporting the autonomy view. Language
production establishes itself as a domain in which morphology may operate “by itself” (Aronoff,
1994) without recourse to meaning.