Infant directed speech and the development of speech perception: Enhancing development or an unintended consequence?

Infant directed speech (IDS) is a speech register characterized by simpler sentences, a slower rate, and more variable prosody. Recent work has implicated it in more subtle aspects of language development. Kuhl et al. (1997) demonstrated that segmental cues for vowels are affected by IDS in a way that may enhance development: the average locations of the extreme “point” vowels (/a/, /i/ and /u/) are further apart in acoustic space. If infants learn speech categories, in part, from the statistical distributions of such cues, these changes may specifically enhance speech category learning. We revisited this by asking (1) if these findings extend to a new cue (Voice Onset Time, a cue for voicing); (2) whether they extend to the interior vowels which are much harder to learn and/or discriminate; and (3) whether these changes may be an unintended phonetic consequence of factors like speaking rate or prosodic changes associated with IDS. Eighteen caregivers were recorded reading a picture book including minimal pairs for voicing (e.g., beach/peach) and a variety of vowels to either an adult or their infant. Acoustic measurements suggested that VOT was different in IDS, but not in a way that necessarily supports better development, and that these changes are almost entirely due to slower rate of speech of IDS. Measurements of the vowel suggested that in addition to changes in the mean, there was also an increase in variance, and statistical modeling suggests that this may counteract the benefit of any expansion of the vowel space. As a whole this suggests that changes in segmental cues associated with IDS may be an unintended by-product of the slower rate of speech and different prosodic structure, and do not necessarily derive from a motivation to enhance development.     

It's Taking Shape: Shared Object Features Influence Novel Noun Generalizations

Children's early noun vocabularies are dominated by names for shape‐based categories. However, along with shape, material and colour are also important features of many early categories. In the current study, we investigate how the number of shared features among objects influences children's novel noun generalizations, explanations for these generalizations and spontaneous speech. Preschool children and adults were presented with test objects that shared only one feature (e.g. shape) or that shared two features (e.g. material and colour). After each trial, participants were asked, ‘how did you know that was your [novel name]?’ Overall, participants generalized novel names on the basis of shape more when objects shared shape and a second feature with the exemplar. All participants provided shape‐based explanations of their choices, but explanations were increasingly more abstract across development. Finally, children's spontaneous speech was dominated by references to the objects' shape, and this did not change across development or number of shared features. Overall, these data demonstrate that the shape bias is enhanced when objects share shape and a second feature but weakened for 3‐year‐old children when objects share two non‐shape features. These findings have implications for our understanding of how children learn names for objects that belong to multiple categories. Copyright © 2012 John Wiley & Sons, Ltd.     

噪音背景对二语语音感知的影响

日常言语交流常常会遇到各种噪音的干扰。研究表明, 噪音所产生的能量掩蔽和信息掩蔽会给语音感知带来较大影响。在感知地道的二语语音时, 二语者在各种噪音条件下所受干扰通常比母语者更大, 其表现随噪音类型、水平和目标音位特征的不同而变化; 同时, 二语者的感知也存在较大个体差异, 这是多种因素影响的结果。在噪音下感知带有各种外国腔的二语口音时, 母语者的表现差于其对地道母语语音的感知; 二语经历贫乏的二语者则对与自己口音类似的外国腔感知较好, 但二语经历较长的二语者在感知中却表现出较大灵活性。     

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。     

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.     

Categorical perception: effects of the extent and rate of spectral change

ABSTRACT

Two experiments evaluated a potential explanation of categorical perception (CP) for place of articulation – namely, that listeners derive limited information from rapid spectral changes. Experiment 1 examined vowel context effects for /b/–/d/ continua that included consonant–vowel tokens with F2 onset frequencies that varied systematically from the F2 frequencies of their corresponding steady-states. Phoneme categorisation sharply shifted with F2 direction at locations along the continuum where discrimination performance peaked, indicating CP. Experiment 2 compared findings for a replicated condition against conditions with vowels reduced to match consonant duration or consonants extended to match vowels. CP was similarly obtained for replicated and vowel-reduced conditions. However, listeners frequently perceived diphthongs centrally on the consonant-extended continuum. Some listeners demonstrated CP, although aggregate performance appeared more continuous. These experiments indicate a model based upon the perceived direction of frequency transitions.     

Pointing gestures as a cognitive tool in young children: experimental evidence

This article explores the possible cognitive function associated with pointing gestures from a Vygotskian perspective. In Study 1, 39 children who were 2-4 years of age were observed in a solitary condition while solving a mnemonic task with or without an explicit memory demand. A discriminant analysis showed that children used noncommunicative pointing gestures only in the task with an explicit memory demand. In Study 2, 39 children who were 4-6 years of age completed an attentional task with and without the possibility of pointing. An analysis of variance showed that only those children who spontaneously pointed to solve the first task performed significantly worse in a second condition where pointing was impossible. These results suggest that besides its social interactive functions, pointing may also subserve private cognitive functions for children.     

Individual differences in children's private speech: Consistency across tasks, timepoints, and contexts

Children often talk themselves through their activities. They produce private speech (PS), which is internalized to form inner speech (silent verbal thought). Twenty-five 8-10-year-olds completed four tasks in a laboratory context (Tower of London, digit span, and two measures of spatial IQ). PS production was recorded. Eleven months later, the same participants completed the Tower of London and academic numeracy tasks, again in a laboratory context, as well as numeracy tasks in a classroom context. Rates of PS production and its level of internalization showed large positive correlations across time, tasks, and contexts. The results are interpreted in terms of the psychometric properties of PS production and are taken as evidence for the development of a domain-general system for verbal self-regulation in childhood.     

Characteristics of inner reading voices

This study examined the phenomenological characteristics of inner speech during silent reading (inner reading voices or IRVs), a type of inner speech that may be particularly amenable to empirical study. A survey was conducted in the general population to assess IRV frequency, location, number, identity, and controllability, and auditory qualities of IRVs. Of 570 survey respondents, 80.7% reported sometimes or always hearing an inner voice during silent reading, and the remaining 19.3% reported always understanding words being read without hearing an inner voice. Results indicated that IRVs are a routine experience for many, with 34.2% of respondents with IRVs hearing an IRV every time something was read, and 45% reporting an IRV often. Most respondents reported IRVs with specific auditory qualities such as gender, accent, pitch, loudness, and emotional tone. IRVs were reported in participants' own voices, as well as in the voices of other people. Some respondents reported being unable to control any aspect of their IRVs, while others could control one or several aspects. These results indicate that there is considerable individual variation in inner speech during silent reading.     

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.