The selective impairment of phonological processing in speech production

We report the naming performance of a patient (DM) with a fluent progressive aphasia who made phonological errors in all language production tasks. The pattern of errors in naming was strikingly clear: DM made very many phonological errors that resulted almost always in nonword responses. The complete absence of semantic errors and the very low ratio of formal errors relative to nonword errors (1.6:30.3) in DM's performance are discussed in the context of recent claims about the nature of naming deficits in fluent aphasics. We argue that DM's performance makes highly improbable the claim that fluent aphasia results from global lesions affecting all levels of the lexical access system equally.     

Additivity of semantic and phonological effects: Evidence from speech production in Mandarin

A number of previous studies using picture–word interference (PWI) tasks conducted with speakers of Western languages have demonstrated non-additive effects of semantic and form overlap between pictures and words, which may indicate underlying non-discrete processing stages in lexical retrieval. The present study used Mandarin speakers and presented Chinese characters as distractors. In two experiments, we crossed semantic relatedness with “pure” phonological (i.e., orthographically unrelated) relatedness and found statistically additive effects. In a third experiment, semantic relatedness was crossed with orthographic overlap (phonological overlap was avoided), and once again we found an additive pattern. The results are discussed with regard to possible cross-linguistic differences between Western and non-Western languages in terms of phonological encoding, as well as concerning the locus of relatedness effects in PWI tasks.     

Practice effects on speech production planning: evidence from slips of the tongue in spontaneous vs. preplanned speech in Japanese

The present study addresses the question of how practice in expressing the content to be conveyed in a specific situation influences speech production planning processes. A comparison of slips of the tongue in Japanese collected from spontaneous everyday conversation and those collected from largely preplanned conversation in live-broadcast TV programs reveals that, although there are those aspects of speech production planning that are unaffected by practice, there are various practice effects, most of which can be explained in terms of automatization of the processing of content, resulting in shifts in the loci of errors.     

The influence of phonological similarity neighborhoods on speech production

The influence of phonological similarity neighborhoods on the speed and accuracy of speech production was investigated with speech-error elicitation and picture-naming tasks. The results from 2 speech-error elicitation techniques-the spoonerisms of laboratory induced predisposition technique (B. J. Baars, 1992; B. J. Baars & M. T. Motley, 1974; M. T. Motley & B. J. Baars, 1976) and tongue twisters-showed that more errors were elicited for words with few similar sounding words (i.e., a sparse neighborhood) than for words with many similar sounding words (i.e., a dense neighborhood). The results from 3 picture-naming tasks showed that words with sparse neighborhoods were also named more slowly than words with dense neighborhoods. These findings demonstrate that multiple word forms are activated simultaneously and influence the speed and accuracy of speech production. The implications of these findings for current models of speech production are discussed.     

Sequencing, speech production, and selective effects of aging on phonological and morphological speech errors

To test age-linked predictions of node structure theory (NST) and other theories, young and older adults performed a task that elicited large numbers of phonological and morphological speech errors. Stimuli were visually presented words containing either /p/ or /b/, and participants changed the /p/ to /b/ or vice versa and produced the resulting word as quickly as possible. For example, the correct response was "bunk" for the stimulus PUNK, and "ripped" for RIBBED. Consistent with NST predictions, the elicited speech errors exhibited selective effects of aging. Some error types decreased with aging. For example, young adults produced more nonsequential substitution errors (as a percentage of total errors) than older adults (e.g., intended bills misproduced as "gills"). However, other error types remained constant or increased with aging. For example, older adults produced more omission errors than young adults, especially omissions involving inflectional endings (e.g. intended ripped misproduced as "np"). In addition, older adults exhibited special difficulties with 2 types of phonological and morphological sequencing processes.     

The link between speech perception and production is phonological and abstract: evidence from the shadowing task

This study reports a shadowing experiment, in which one has to repeat a speech stimulus as fast as possible. We tested claims about a direct link between perception and production based on speech gestures, and obtained two types of counterevidence. First, shadowing is not slowed down by a gestural mismatch between stimulus and response. Second, phonetic detail is more likely to be imitated in a shadowing task if it is phonologically relevant. This is consistent with the idea that speech perception and speech production are only loosely coupled, on an abstract phonological level.     

音乐学习对语言加工的促进作用

音乐学习可以增强个体的艺术素养,同时,音乐学习对其他认知加工过程尤其是语言学习还有正面的促进作用。近年来国内外学者主要围绕着音乐家、音乐学习障碍个体开展了一系列相关工作,同时还进行了相关的追踪研究。值得注意的是,有关音乐学习促进语言加工的实证依据主要来自横断研究,还需要更多的纵向追踪研究来进一步提供因果关系的证据。这方面的工作将最终促进音乐学习与训练在教育与医疗领域的广泛应用。     

Role of left posterior superior temporal gyrus in phonological processing for speech perception and production

Models of both speech perception and speech production typically postulate a processing level that involves some form of phonological processing. There is disagreement, however, on the question of whether there are separate phonological systems for speech input versus speech output. We review a range of neuroscientific data that indicate that input and output phonological systems partially overlap. An important anatomical site of overlap appears to be the left posterior superior temporal gyrus. We then present the results of a new event-related functional magnetic resonance imaging (fMRI) experiment in which participants were asked to listen to and then (covertly) produce speech. In each participant, we found two regions in the left posterior superior temporal gyrus that responded both to the perception and production components of the task, suggesting that there is overlap in the neural systems that participate in phonological aspects of speech perception and speech production. The implications for neural models of verbal working memory are also discussed in connection with our findings.     

Contrasting effects of phonological priming in aphasic word production

Two fluent aphasics, IG and GL, performed a phonological priming task in which they repeated an auditory prime then named a target picture. The two patients both had selective deficits in word production: they were at or near ceiling on lexical comprehension tasks, but were significantly impaired in picture naming. IG's naming errors included both semantic and phonemic paraphasias, as well as failures to respond, whereas GL's errors were mainly phonemic and formal paraphasias. The two patients responded very differently to phonological priming: IG's naming was facilitated (both accuracy and speed) only by begin-related primes (e.g. ferry-feather), whereas GL benefited significantly only from end-related primes (e.g. brother-feather), showing no more than a facilitatory trend with begin-related primes. We interpret these results within a two-stage model of word production, in which begin-related and end-related primes are said to operate at different stages. We then discuss implications for models of normal and aphasic word production in general and particularly with respect to sequential aspects of the phonological encoding process.     

The power of powerless speech: The effects of speech style and task interdependence on status conferral

Two studies examine the effects of speech styles and task interdependence on status conferral judgments. In both studies, participants were exposed to an individual who used either a powerful or powerless speech style in a low or high task interdependence group, and made judgments about the amount of status to confer to the individual. When task interdependence was low, participants conferred more status to powerful speakers, whereas when interdependence was high, participants conferred more status to powerless speakers. Furthermore, Study 2 demonstrated that speech styles influenced trait inferences about the speaker (agency and communality), but these traits were weighted differently in status conferral judgments across groups. These findings provide insight into both the relationship between observed behaviors and status positions and the decision process underlying status conferral judgments.     

The roles of family history of dyslexia,language, speech production and phonological processing in predicting literacy progress

It is well established that speech, language and phonological skills are closely associated with literacy, and that children with a family risk of dyslexia (FRD) tend to show deficits in each of these areas in the preschool years. This paper examines what the relationships are between FRD and these skills, and whether deficits in speech, language and phonological processing fully account for the increased risk of dyslexia in children with FRD. One hundred and fifty‐three 4–6‐year‐old children, 44 of whom had FRD, completed a battery of speech, language, phonology and literacy tasks. Word reading and spelling were retested 6 months later, and text reading accuracy and reading comprehension were tested 3 years later. The children with FRD were at increased risk of developing difficulties in reading accuracy, but not reading comprehension. Four groups were compared: good and poor readers with and without FRD. In most cases good readers outperformed poor readers regardless of family history, but there was an effect of family history on naming and nonword repetition regardless of literacy outcome, suggesting a role for speech production skills as an endophenotype of dyslexia. Phonological processing predicted spelling, while language predicted text reading accuracy and comprehension. FRD was a significant additional predictor of reading and spelling after controlling for speech production, language and phonological processing, suggesting that children with FRD show additional difficulties in literacy that cannot be fully explained in terms of their language and phonological skills.     

Atypical speech lateralization in adults with developmental coordination disorder demonstrated using functional transcranial Doppler ultrasound

Research using clinical populations to explore the relationship between hemispheric speech lateralization and handedness has focused on individuals with speech and language disorders, such as dyslexia or specific language impairment (SLI). Such work reveals atypical patterns of cerebral lateralization and handedness in these groups compared to controls. There are few studies that examine this relationship in people with motor coordination impairments but without speech or reading deficits, which is a surprising omission given the prevalence of theories suggesting a common neural network underlying both functions. We use an emerging imaging technique in cognitive neuroscience; functional transcranial Doppler (fTCD) ultrasound, to assess whether individuals with developmental coordination disorder (DCD) display reduced left‐hemisphere lateralization for speech production compared to control participants. Twelve adult control participants and 12 adults with DCD, but no other developmental/cognitive impairments, performed a word‐generation task whilst undergoing fTCD imaging to establish a hemispheric lateralization index for speech production. All participants also completed an electronic peg‐moving task to determine hand skill. As predicted, the DCD group showed a significantly reduced left lateralization pattern for the speech production task compared to controls. Performance on the motor skill task showed a clear preference for the dominant hand across both groups; however, the DCD group mean movement times were significantly higher for the non‐dominant hand. This is the first study of its kind to assess hand skill and speech lateralization in DCD. The results reveal a reduced leftwards asymmetry for speech and a slower motor performance. This fits alongside previous work showing atypical cerebral lateralization in DCD for other cognitive processes (e.g., executive function and short‐term memory) and thus speaks to debates on theories of the links between motor control and language production.     

Neighbourhood effects on error rates in speech production

Models of speech production differ on whether phonological neighbourhoods should affect processing, and on whether effects should be facilitatory or inhibitory. Inhibitory effects of large neighbourhoods have been argued to underlie apparent anti-frequency effects, whereby high-frequency default features are more prone to mispronunciation errors than low-frequency nondefault features. Data from the original SLIPs experiments that found apparent anti-frequency effects are analysed for neighbourhood effects. Effects are facilitatory: errors are significantly less likely for words with large numbers of neighbours that share the characteristic that is being primed for error ("friends"). Words in the neighbourhood that do not share the target characteristic ("enemies") have little effect on error rates. Neighbourhood effects do not underlie the apparent anti-frequency effects. Implications for models of speech production are discussed.     

Inhibitory control and the speech patterns of second language users

Inhibitory control (IC), an ability to suppress irrelevant and/or conflicting information, has been found to underlie performance on a variety of cognitive tasks, including bilingual language processing. This study examines the relationship between IC and the speech patterns of second language (L2) users from the perspective of individual differences. While the majority of studies have supported the role of IC in bilingual language processing using single‐word production paradigms, this work looks at inhibitory processes in the context of extended speech, with a particular emphasis on disfluencies. We hypothesized that the speech of individuals with poorer IC would be characterized by reduced fluency. A series of regression analyses, in which we controlled for age and L2 proficiency, revealed that IC (in terms of accuracy on the Stroop task) could reliably predict the occurrence of reformulations and the frequency and duration of silent pauses in L2 speech. No statistically significant relationship was found between IC and other L2 spoken output measures, such as repetitions, filled pauses, and performance errors. Conclusions focus on IC as one out of a number of cognitive functions in the service of spoken language production. A more qualitative approach towards the question of whether L2 speakers rely on IC is advocated.     

言语想象的神经机制

言语想象不仅在大脑预处理机制方面起到重要的作用,还是目前脑机接口领域研究的热点。与正常言语产生过程相比,言语想象的理论模型、激活脑区、神经传导路径等均与其有较多相似之处。而言语障碍群体的言语想象、想象有意义的词语和句子时的脑神经机制与正常言语产生存在差异。鉴于人类言语系统的复杂性,言语想象的神经机制研究还面临一系列挑战,未来研究可在言语想象质量评价工具及神经解码范式、脑控制回路、激活通路、言语障碍群体的言语想象机制、词语和句子想象的脑神经信号等方面进一步探索,为有效提高脑机接口的识别率提供依据,为言语障碍群体的沟通提供便利。     

Neural correlates of phonological processing in speech sound disorder: a functional magnetic resonance imaging study

Speech sound disorders (SSD) are the largest group of communication disorders observed in children. One explanation for these disorders is that children with SSD fail to form stable phonological representations when acquiring the speech sound system of their language due to poor phonological memory (PM). The goal of this study was to examine PM in individuals with histories of SSD employing functional MR imaging (fMRI). Participants were six right-handed adolescents with a history of early childhood SSD and seven right-handed matched controls with no history of speech and language disorders. We performed an fMRI study using an overt non-word repetition (NWR). Right lateralized hypoactivation in the inferior frontal gyrus and middle temporal gyrus was observed. The former suggests a deficit in the phonological processing loop supporting PM, while the later may indicate a deficit in speech perception. Both are cognitive processes involved in speech production. Bilateral hyperactivation observed in the pre and supplementary motor cortex, inferior parietal, supramarginal gyrus and cerebellum raised the possibility of compensatory increases in cognitive effort or reliance on the other components of the articulatory rehearsal network and phonologic store. These findings may be interpreted to support the hypothesis that individuals with SSD may have a deficit in PM and to suggest the involvement of compensatory mechanisms to counteract dysfunction of the normal network.     

口语产生中词频效应、音节频率效应和语音促进效应的认知年老化

采用图画-词汇干扰实验范式,考察了汉语口语产生过程中词频与音节频率效应、语音促进效应的认知年老化现象及其认知机制。结果发现,老年组的图画命名时间长于青年组,且老年组的词频效应和音节频率效应高于青年组,而语音相关效应低于青年组。老年组中词频和音节频率存在两因素交互作用,青年组则没有,这表明随着年龄增加,老年人的心理词典中不仅语义水平和音韵水平之间的联结强度变弱,而且信息之间的作用模式发生了变化。研究结果为激活不充分假设或传输不足假设提供了证据。     

The effects of speech production and speech comprehension on simulated driving performance

We performed two experiments comparing the effects of speech production and speech comprehension on simulated driving performance. In both experiments, participants completed a speech task and a simulated driving task under single‐ and dual‐task conditions, with language materials matched for linguistic complexity. In Experiment 1, concurrent production and comprehension resulted in more variable velocity compared to driving alone. Experiment 2 replicated these effects in a more difficult simulated driving environment, with participants showing larger and more variable headway times when speaking or listening while driving than when just driving. In both experiments, concurrent production yielded better control of lane position relative to single‐task performance; concurrent comprehension had little impact on control of lane position. On all other measures, production and comprehension had very similar effects on driving. The results show, in line with previous work, that there are detrimental consequences for driving of concurrent language use. Our findings imply that these detrimental consequences may be roughly the same whether drivers are producing speech or comprehending it. Copyright © 2005 John Wiley & Sons, Ltd.     

The phonological loop model of working memory: An ERP study of irrelevant speech and phonological similarity effects

The phonological loop model for retention of auditory verbal material in working memory, developed by Baddeley, assumes that irrelevant speech and phonological similarity influence only one and the same element of the system—that is, the phonological short-term store. We tested this idea by recording eventrelated potentials (ERPs) to auditorily presented letters that were phonologically similar or dissimilar and were to be memorized in the presence of more or less disturbing irrelevant speech. Irrelevant speech and phonological similarity caused ERP effects with clearly different scalp topographies, indicating that these factors influence different brain systems and hence probably different cognitive elements. Moreover, ERPs indicated that the phonological similarity effect might involve processes at the level of phonological analysis. Our data also support recent suggestions that the irrelevant speech effect is not based on the phonological similarity between relevant and irrelevant material, but on the phonological variability within the irrelevant stream.