Phonological acquisition depends on the timing of speech sounds: Deconvolution EEG modeling across the first five years

The late development of fast brain activity in infancy restricts initial processing abilities to slow information. Nevertheless, infants acquire the short-lived speech sounds of their native language during their first year of life. Here, we trace the early buildup of the infant phoneme inventory with naturalistic electroencephalogram. We apply the recent method of deconvolution modeling to capture the emergence of the feature-based phoneme representation that is known to govern speech processing in the mature brain. Our cross-sectional analysis uncovers a gradual developmental increase in neural responses to native phonemes. Critically, infants appear to acquire those phoneme features first that extend over longer time intervals-thus meeting infants' slow processing abilities. Shorter-lived phoneme features are added stepwise, with the shortest acquired last. Our study shows that the ontogenetic acceleration of electrophysiology shapes early language acquisition by determining the duration of the acquired units.

Language and communication skills in multilingual children on the autism spectrum: A systematic review

LAY ABSTRACT

Both parents and service providers have voiced concerns about the potential negative impact of exposure to multiple languages on the language and communication skills of autistic children. The current literature review summarized research that assessed the language and communication skills of multilingual autistic children in comparison with their autistic and nonautistic peers. After a comprehensive search, 22 relevant publications were identified that met the inclusion criteria of the current review. Thirteen studies used both direct (directly administered screening/diagnostic tools) and indirect language assessments (e.g. parent questionnaires). Receptive and expressive vocabulary was the most frequently assessed language skill. Available research does not support the assumption that bilingualism has negative effects on the language and communication skills of autistic children. The language and communication skills of multilingual autistic children frequently resembled their monolingual autistic peers in both strengths and areas of growth. Preliminary findings indicate that multilingual autistic children may share some advantages of multilingualism with their multilingual nonautistic peers. Studies often excluded participants with intellectual disabilities or complex communication needs, which means that a large population of autistic children is not yet represented in research about the effects of multilingualism.

Perception of accent in bilingual French/American-English children by native adult speakers

In a previous study, Dodane and Bijeljac-Babic (2017) found that French/AmericanEnglish children aged 3;6 to 6;0, bilingual from birth, produced disyllabic words which had acoustic properties for lexical stress (f0, syllable duration and intensity) that differed from those of monolingual peers, showing cross-linguistic influences. In order to check whether these acoustic differences between the productions of bilingual children and those of their monolingual French- or American English-speaking peers were perceptible by native monolingual adults, we investigated the perception of these words by French and American English native speakers. Using an Elo rating task, participants were asked to indicate in each trial which word out of two competitors was produced by a bilingual child. Words were produced by French- or American English-speaking monolingual children and by two groups of bilinguals, one dominant in French and the other in American-English. The results clearly show that both French and American English monolingual adults were successful in distinguishing the bilingual children from their monolingual peers, but only if they were not dominant in the language of the raters. The relationship between the acoustic correlates of word stress produced by children and the perception of some "accent" by native adult speakers seems more intricate than expected and is further discussed.

Infant learning of words in a typologically distant nonnative language

Infants attune to their native language during the first two years of life, as attested by decreases in the processing of nonnative phonological sounds and reductions in the range of possible sounds accepted as labels for native words. The present study shows that French-learning infants aged 1;8 can learn new words in an unfamiliar language, Cantonese, after just 6 repetitions of each word. This shows that word learning in a nonnative language remains possible during the second year of life even in a nonnative language that is typologically distinct from the native language.

Bridging ears and eyes when learning spoken words: On the effects of bilingual experience at 30 months

From the very first moments of their lives, infants selectively attend to the visible orofacial movements of their social partners and apply their exquisite speech perception skills to the service of lexical learning. Here we explore how early bilingual experience modulates children's ability to use visible speech as they form new lexical representations. Using a cross-modal word-learning task, bilingual children aged 30 months were tested on their ability to learn new lexical mappings in either the auditory or the visual modality. Lexical recognition was assessed either in the same modality as the one used at learning ('same modality' condition: auditory test after auditory learning, visual test after visual learning) or in the other modality ('cross-modality' condition: visual test after auditory learning, auditory test after visual learning). The results revealed that like their monolingual peers, bilingual children successfully learn new words in either the auditory or the visual modality and show cross-modal recognition of words following auditory learning. Interestingly, as opposed to monolinguals, they also demonstrate cross-modal recognition of words upon visual learning. Collectively, these findings indicate a bilingual edge in visual word learning, expressed in the capacity to form a recoverable cross-modal representation of visually learned words.

One language or two? Navigating cross-language conflict in statistical word segmentation

Bilingual infants must navigate the similarities and differences between their languages to achieve native proficiency in childhood. Bilinguals learning to find individual words in fluent speech face the possibility of conflicting cues to word boundaries across their languages. Despite this challenge, bilingual infants typically begin to segment and learn words in both languages around the same time as monolinguals. It is possible that early bilingual experience may support infants' abilities to track regularities relevant for word segmentation separately across their languages. In a dual speech stream statistical word segmentation task, we assessed whether 16-month-old infants could track syllable co-occurrence regularities in two artificial languages despite conflicting information across the languages. We found that bilingual, but not monolingual, infants were able to segment the dual speech streams using statistical regularities. Although the two language groups did not differ on secondary measures of cognitive and linguistic development, bilingual infants' real-world experience with bilingual speakers was predictive of their performance in the dual language statistical segmentation task.

Inside bilingualism: Language background modulates selective attention to a talker's mouth

Previous findings indicate that bilingual Catalan/Spanish-learning infants attend more to the highly salient audiovisual redundancy cues normally available in a talker's mouth than do monolingual infants. Presumably, greater attention to such cues renders the challenge of learning two languages easier. Spanish and Catalan are, however, rhythmically and phonologically close languages. This raises the possibility that bilinguals only rely on redundant audiovisual cues when their languages are close. To test this possibility, we exposed 15-month-old and 4- to 6-year-old close-language bilinguals (Spanish/Catalan) and distant-language bilinguals (Spanish/"other") to videos of a talker uttering Spanish or Catalan (native) and English (non-native) monologues and recorded eye-gaze to the talker's eyes and mouth. At both ages, the close-language bilinguals attended more to the talker's mouth than the distant-language bilinguals. This indicates that language proximity modulates selective attention to a talker's mouth during early childhood and suggests that reliance on the greater salience of audiovisual speech cues depends on the difficulty of the speech-processing task.

Segmentation of tongue shapes during vowel production in magnetic resonance images based on statistical modelling

Quantification of the anatomic and functional aspects of the tongue is pertinent to analyse the mechanisms involved in speech production. Speech requires dynamic and complex articulation of the vocal tract organs, and the tongue is one of the main articulators during speech production. Magnetic resonance imaging has been widely used in speech-related studies. Moreover, the segmentation of such images of speech organs is required to extract reliable statistical data. However, standard solutions to analyse a large set of articulatory images have not yet been established. Therefore, this article presents an approach to segment the tongue in two-dimensional magnetic resonance images and statistically model the segmented tongue shapes. The proposed approach assesses the articulator morphology based on an active shape model, which captures the shape variability of the tongue during speech production. To validate this new approach, a dataset of mid-sagittal magnetic resonance images acquired from four subjects was used, and key aspects of the shape of the tongue during the vocal production of relevant European Portuguese vowels were evaluated.

Learning Spoken Words via the Ears and Eyes: Evidence from 30-Month-Old Children

From the very first moments of their lives, infants are able to link specific movements of the visual articulators to auditory speech signals. However, recent evidence indicates that infants focus primarily on auditory speech signals when learning new words. Here, we ask whether 30-month-old children are able to learn new words based solely on visible speech information, and whether information from both auditory and visual modalities is available after learning in only one modality. To test this, children were taught new lexical mappings. One group of children experienced the words in the auditory modality (i.e., acoustic form of the word with no accompanying face). Another group experienced the words in the visual modality (seeing a silent talking face). Lexical recognition was tested in either the learning modality or in the other modality. Results revealed successful word learning in either modality. Results further showed cross-modal recognition following an auditory-only, but not a visual-only, experience of the words. Together, these findings suggest that visible speech becomes increasingly informative for the purpose of lexical learning, but that an auditory-only experience evokes a cross-modal representation of the words.