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The initial stages of language learning involve a critical interaction between infants' environmental experience and their developing brains. The past several decades of research have produced important behavioral evidence of the many factors influencing this process, both on the part of the child and on the part of the environment that the child is in. The application of neurophysiological techniques to the study of early development has been augmenting these findings at a rapid pace. While the result is an accrual of data bridging the gap between brain and behavior, much work remains to make the link between behavioral evidence of infants' emerging sensitivities and neurophysiological evidence of changes in how their brains process information. Here we review the background behavioral data on how salience and familiarity in the auditory signal shape initial language learning. We follow this with a summary of more recent evidence of changes in infants' brain activity in response to specific aspects of speech. Our goal is to examine language learning through the lens of brain/environment interactions, ultimately focusing on changes in cortical processing of speech across the first year of life. We will ground our examination of recent brain data in the two auditory features initially outlined: salience and familiarity. Our own and others' findings on the influence of these two features reveal that they are key parameters in infants' emerging recognition of structure in the speech signal. Importantly, the evidence we review makes the critical link between behavioral and brain data. We discuss the importance of future work that makes this bridge as a means of moving the study of language development solidly into the domain of brain science.

The effects of bilingualism on vowel perception and cue weighting behaviour have not been established definitively. What influence does heritage bilingualism have on cue weighting of spectral and durational cues? What role does the duration cue play in cue weighting behaviour of heritage bilinguals: is it universally accessible or related to the first language? Purpose: This study examines the perception and cue weighting of child heritage bilinguals to assess whether exposure to multiple acoustic systems has an effect on cue weighting. Design: Bilinguals with a language containing a durational vowel contrast (Moroccan-Arabic) or a non-durational contrast (Turkish) were tested in order to explore cue preference and cue weighting behaviour for the multiple cued Dutch [ɑ]-[a:] contrast: their alternate first language. Data and analysis: An identification task was performed for the Dutch [ɑ] and [a:]. The F1 and F2 were logarithmically manipulated, in equal steps for the spectral and durational cue, creating a seven-step continuum. The analysis revealed cue preference by examining cue usage and relative cue weight. Conclusions: Dutch monolinguals use both cues but assign more weight to the spectral cue. Moroccan-Arabic/Dutch heritage speaker (HS) bilinguals use both cues, but weigh the spectral cue more heavily. Turkish/Dutch HS bilinguals rely almost exclusively on the spectral cue. This suggests a transfer from the alternate first language onto the perception of Dutch, regardless of language dominance. Originality: Not much research on the cue weighting behaviour of school-aged heritage bilinguals has been conducted, as this age group is yet to develop their perceptual behaviour completely. The results of this case study show an influence on perceptual behaviour as a result of bilingualism. Significance: This study provides insight into the cue weighting behaviour and cue preference of school-aged heritage bilinguals. [ABSTRACT FROM AUTHOR]

This study explores the influence of bilingualism on the cognitive processing of language and music. Specifically, we investigate how infants learning a non-tone language perceive linguistic and musical pitch and how bilingualism affects cross-domain pitch perception. Dutch monolingual and bilingual infants of 8-9 months participated in the study. All infants had Dutch as one of the first languages. The other first languages, varying among bilingual families, were not tone or pitch accent languages. In two experiments, infants were tested on the discrimination of a lexical ( N = 42) or a violin ( N = 48) pitch contrast via a visual habituation paradigm. The two contrasts shared identical pitch contours but differed in timbre. Non-tone language learning infants did not discriminate the lexical contrast regardless of their ambient language environment. When perceiving the violin contrast, bilingual but not monolingual infants demonstrated robust discrimination. We attribute bilingual infants' heightened sensitivity in the musical domain to the enhanced acoustic sensitivity stemming from a bilingual environment. The distinct perceptual patterns between language and music and the influence of acoustic salience on perception suggest processing diversion and association in the first year of life. Results indicate that the perception of music may entail both shared neural network with language processing, and unique neural network that is distinct from other cognitive functions. [ABSTRACT FROM AUTHOR]

Traffic noise is one of the main pollutants in urban and suburban areas. European authorities have driven several initiatives to study, prevent and reduce the effects of exposure of population to traffic. Recent technological advances have allowed the dynamic computation of noise levels by means ofWireless Acoustic Sensor Networks (WASN) such as that developed within the European LIFE DYNAMAP project. ThoseWASN should be capable of detecting and discarding non-desired sound sources from road traffic noise, denoted as anomalous noise events (ANE), in order to generate reliable noise level maps. Due to the local, occasional and diverse nature of ANE, some works have opted to artificially build ANE databases at the cost of misrepresentation. This work presents the production and analysis of a real-life environmental audio database in two urban and suburban areas specifically conceived for anomalous noise events' collection. A total of 9 h 8 min of labelled audio data is obtained differentiating among road traffic noise, background city noise and ANE. After delimiting their boundaries manually, the acoustic salience of the ANE samples is automatically computed as a contextual signal-to-noise ratio (SNR). The analysis of the real-life environmental database shows high diversity of ANEs in terms of occurrences, durations and SNRs, as well as confirming both the expected differences between the urban and suburban soundscapes in terms of occurrences and SNRs, and the rare nature of ANE. [ABSTRACT FROM AUTHOR]

Purpose: Facing previous mixed findings between monolingual and bilingual infants’ phonetic development during perceptual reorganization, the current study aims at examining the perceptual development of a native vowel contrast (/I/-/i/) by Dutch monolingual and bilingual infants. Design: We tested 390 Dutch monolingual and bilingual infants from 5 to 15 months of age through a visual habituation paradigm. Data and analysis: Mixed-effect model analyses were conducted within 320 infants, with infants’ log10 transformed looking time as the dependent variable, age (4-level) and language background (2-level) as the fixed factors, and participant and order (2-level) as the random factors. Conclusions: All infants show weak initial sensitivity to the contrast regardless of language background(s), and sensitivity improves with age. By the second half of the first year, infants discriminate the contrast, indicating the emergence of the relevant vowel categories. In addition, a perceptual lead is observed in bilingual infants, probably due to: 1) a perceptual transfer from the close-category counterpart of the other native language; 2) heightened acoustic sensitivity in bilingual infants given their rich linguistic experience; and 3) a general bilingual cognitive advantage. The influences of contrast salience and bilingualism on language development are discussed. Originality: Overall, these findings constitute an extension of existing work on vowel perception and display a novel acceleration effect for the bilingual infants in phonetic perception. In addition, we propose a novel heightened acoustic sensitivity hypothesis, arguing that bilingual infants may pay more attention to acoustic details in the input than their monolingual peers. Significance: The observed progressive phonetic discrimination pattern of the native contrast contributes to our knowledge in infant language development, and specifically perceptual reorganization patterns, in the first year after birth. The observed acceleration effect, along with its explanations, provides new insights into the influence of bilingualism and potential bilingual advantages in infancy. [ABSTRACT FROM AUTHOR]

The initial stages of language learning involve a critical interaction between infants’ environmental experience and their developing brains. The past several decades of research have produced important behavioral evidence of the many factors influencing this process, both on the part of the child and on the part of the environment that the child is in. The application of neurophysiological techniques to the study of early development has been augmenting these findings at a rapid pace. While the result is an accrual of data bridging the gap between brain and behavior, much work remains to make the link between behavioral evidence of infants' emerging sensitivities and neurophysiological evidence of changes in how their brains process information. Here we review the background behavioral data on how salience and familiarity in the auditory signal shape initial language learning. We follow this with a summary of more recent evidence of changes in infants’ brain activity in response to specific aspects of speech. Our goal is to examine language learning through the lens of brain/environment interactions, ultimately focusing on changes in cortical processing of speech across the first year of life. We will ground our examination of recent brain data in the two auditory features initially outlined: salience and familiarity. Our own and others' findings on the influence of these two features reveal that they are key parameters in infants’ emerging recognition of structure in the speech signal. Importantly, the evidence we review makes the critical link between behavioral and brain data. We discuss the importance of future work that makes this bridge as a means of moving the study of language development solidly into the domain of brain science.

Traffic noise is one of the main pollutants in urban and suburban areas. European authorities have driven several initiatives to study, prevent and reduce the effects of exposure of population to traffic. Recent technological advances have allowed the dynamic computation of noise levels by means of Wireless Acoustic Sensor Networks (WASN) such as that developed within the European LIFE DYNAMAP project. Those WASN should be capable of detecting and discarding non-desired sound sources from road traffic noise, denoted as anomalous noise events (ANE), in order to generate reliable noise level maps. Due to the local, occasional and diverse nature of ANE, some works have opted to artificially build ANE databases at the cost of misrepresentation. This work presents the production and analysis of a real-life environmental audio database in two urban and suburban areas specifically conceived for anomalous noise events’ collection. A total of 9 h 8 min of labelled audio data is obtained differentiating among road traffic noise, background city noise and ANE. After delimiting their boundaries manually, the acoustic salience of the ANE samples is automatically computed as a contextual signal-to-noise ratio (SNR). The analysis of the real-life environmental database shows high diversity of ANEs in terms of occurrences, durations and SNRs, as well as confirming both the expected differences between the urban and suburban soundscapes in terms of occurrences and SNRs, and the rare nature of ANE.

Abstract: Acoustic filter properties of A1 neurons can dynamically adapt to stimulus statistics, classical conditioning, instrumental learning and the changing auditory attentional focus. We have recently developed an experimental paradigm that allows us to view cortical receptive field plasticity on-line as the animal meets different behavioral challenges by attending to salient acoustic cues and changing its cortical filters to enhance performance. We propose that attention is the key trigger that initiates a cascade of events leading to the dynamic receptive field changes that we observe. In our paradigm, ferrets were initially trained, using conditioned avoidance training techniques, to discriminate between background noise stimuli (temporally orthogonal ripple combinations) and foreground tonal target stimuli. They learned to generalize the task for a wide variety of distinct background and foreground target stimuli. We recorded cortical activity in the awake behaving animal and computed on-line spectrotemporal receptive fields (STRFs) of single neurons in A1. We observed clear, predictable task-related changes in STRF shape while the animal performed spectral tasks (including single tone and multi-tone detection, and two-tone discrimination) with different tonal targets. A different set of task-related changes occurred when the animal performed temporal tasks (including gap detection and click-rate discrimination). Distinctive cortical STRF changes may constitute a “task-specific signature”. These spectral and temporal changes in cortical filters occur quite rapidly, within 2min of task onset, and fade just as quickly after task completion, or in some cases, persisted for hours. The same cell could multiplex by differentially changing its receptive field in different task conditions. On-line dynamic task-related changes, as well as persistent plastic changes, were observed at a single-unit, multi-unit and population level. Auditory attention is likely to be pivotal in mediating these task-related changes since the magnitude of STRF changes correlated with behavioral performance on tasks with novel targets. Overall, these results suggest the presence of an attention-triggered plasticity algorithm in A1 that can swiftly change STRF shape by transforming receptive fields to enhance figure/ground separation, by using a contrast matched filter to filter out the background, while simultaneously enhancing the salient acoustic target in the foreground. These results favor the view of a nimble, dynamic, attentive and adaptive brain that can quickly reshape its sensory filter properties and sensori-motor links on a moment-to-moment basis, depending upon the current challenges the animal faces. In this review, we summarize our results in the context of a broader survey of the field of auditory attention, and then consider neuronal networks that could give rise to this phenomenon of attention-driven receptive field plasticity in A1. [Copyright &y& Elsevier]