Parents’ hyper-pitch and low vowel category variability in infant-directed speech are associated with 18-month-old toddlers’ expressive vocabulary

The present study examines the acoustic properties of infant-directed speech (IDS) as compared to adult-directed speech (ADS) in Norwegian parents of 18-month-old toddlers, and whether these properties relate to toddlers’ expressive vocabulary size. Twenty-one parent-toddler dyads from Tromsø, Northern Norway participated in the study. Parents (16 mothers, 5 fathers), speaking a Northern Norwegian dialect, were recorded in the lab reading a storybook to their toddler (IDS register), and to an experimenter (ADS register). The storybook was designed for the purpose of the study, ensuring identical linguistic contexts across speakers and registers, and multiple representations of each of the nine Norwegian long vowels. We examined both traditionally reported measures of IDS: pitch, pitch range, vowel duration and vowel space expansion, but also novel measures: vowel category variability and vowel category distinctiveness. Our results showed that Norwegian IDS, as compared to ADS, had similar characteristics as in previously reported languages: higher pitch, wider pitch range, longer vowel duration, and expanded vowel space area; in addition, it had more variable vowel categories. Further, parents’ hyper-pitch, that is, the within-parent increase in pitch in IDS as compared to ADS, and lower vowel category variability in IDS itself, were related to toddlers' vocabulary. Our results point towards potentially facilitating roles of increase in parents’ pitch when talking to their toddlers and of consistency in vowel production in early word learning

The effect of phonetic production training with visual feedback on the perception and production of foreign speech sounds

Second-language learners often experience major difficulties in producing non-native speech sounds. This paper introduces a training method that uses a real-time analysis of the acoustic properties of vowels produced by non-native speakers to provide them with immediate, trial-by-trial visual feedback about their articulation alongside that of the same vowels produced by native speakers. The Mahalanobis acoustic distance between non-native productions and target native acoustic spaces was used to assess L2 production accuracy. The experiment shows that 1 h of training per vowel improves the production of four non-native Danish vowels: the learners' productions were closer to the corresponding Danish target vowels after training. The production performance of a control group remained unchanged. Comparisons of pre- and post-training vowel discrimination performance in the experimental group showed improvements in perception. Correlational analyses of training-related changes in production and perception revealed no relationship. These results suggest, first, that this training method is effective in improving non-native vowel production. Second, training purely on production improves perception. Finally, it appears that improvements in production and perception do not systematically progress at equal rates within individuals

Young children’s screen time during the first COVID-19 lockdown in 12 countries

Older children with online schooling requirements, unsurprisingly, were reported to have increased screen time during the frst COVID-19 lockdown in many countries. Here, we ask whether younger children with no similar online schooling requirements also had increased screen time during lockdown. We examined children’s screen time during the frst COVID-19 lockdown in a large cohort (n= 2209) of 8-to-36-month-olds sampled from 15 labs across 12 countries. Caregivers reported that toddlers with no online schooling requirements were exposed to more screen time during lockdown than before lockdown. While this was exacerbated for countries with longer lockdowns, there was no evidence that the increase in screen time during lockdown was associated with socio-demographic variables, such as child age and socio-economic status (SES). However, screen time during lockdown was negatively associated with SES and positively associated with child age, caregiver screen time, and attitudes towards children’s screen time. The results highlight the impact of the COVID-19 lockdown on young children’s screen time

Quantifying sources of variability in infancy research using the infant-directed-speech preference

Psychological scientists have become increasingly concerned with issues related to methodology and replicability, and infancy researchers in particular face specific challenges related to replicability: For example, high-powered studies are difficult to conduct, testing conditions vary across labs, and different labs have access to different infant populations. Addressing these concerns, we report on a large-scale, multisite study aimed at (a) assessing the overall replicability of a single theoretically important phenomenon and (b) examining methodological, cultural, and developmental moderators. We focus on infants’ preference for infant-directed speech (IDS) over adult-directed speech (ADS). Stimuli of mothers speaking to their infants and to an adult in North American English were created using seminaturalistic laboratory-based audio recordings. Infants’ relative preference for IDS and ADS was assessed across 67 laboratories in North America, Europe, Australia, and Asia using the three common methods for measuring infants’ discrimination (head-turn preference, central fixation, and eye tracking). The overall meta-analytic effect size (Cohen’s d) was 0.35, 95% confidence interval = [0.29, 0.42], which was reliably above zero but smaller than the meta-analytic mean computed from previous literature (0.67). The IDS preference was significantly stronger in older children, in those children for whom the stimuli matched their native language and dialect, and in data from labs using the head-turn preference procedure. Together, these findings replicate the IDS preference but suggest that its magnitude is modulated by development, native-language experience, and testing procedure. (This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 798658.

COVID-19 first lockdown as a window into language acquisition: Associations between caregiver-child activities and vocabulary gains

The COVID-19 pandemic, and the resulting closure of daycare centers worldwide, led to unprecedented changes in children’s learning environments. This period of increased time at home with caregivers, with limited access to external sources (e.g., daycares) provides a unique opportunity to examine the associations between the caregiver-child activities and children’s language development. The vocabularies of 1742 children aged 8-36 months across 13 countries and 12 languages were evaluated at the beginning and end of the first lockdown period in their respective countries (from March to September 2020). Children who had less passive screen exposure and whose caregivers read more to them showed larger gains in vocabulary development during lockdown, after controlling for SES and other caregiver-child activities. Children also gained more words than expected (based on normative data) during lockdown; either caregivers were more aware of their child’s development or vocabulary development benefited from intense caregiver-child interaction during lockdown

COVID-19 first lockdown as a window into language acquisition : associations between caregiver-child activities and vocabulary gains

The COVID-19 pandemic, and the resulting closure of daycare centers worldwide, led to unprecedented changes in children’s learning environments. This period of increased time at home with caregivers, with limited access to external sources (e.g., daycares) provides a unique opportunity to examine the associations between the caregiver-child activities and children’s language development. The vocabularies of 1742 children aged8-36 months across 13 countries and 12 languages were evaluated at the beginning and end of the first lockdown period in their respective countries(from March to September 2020). Children who had less passive screen exposure and whose caregivers read more to them showed larger gains in vocabulary development during lockdown, after controlling for SES and other caregiver-child activities. Children also gained more words than expected (based on normative data) during lockdown; either caregivers were more aware of their child’s development or vocabulary development benefited from intense caregiver-child interaction during lockdown

Interactions between native and non-native vowels in French-Danish contact: production training study

Jan 2017Speakers who acquire a foreign language (L2) in adulthood (and even earlier), often experience major difficulties in producing non-native speech sounds, a phenomenon commonly known as having a foreign accent. These difficulties in non-native phonetic production are attributed to difficulties in distinguishing similar to native non-native sounds. Consequently, native sounds are used to produce similar non-native phones. Production training techniques whereby speakers receive feedback that compares their productions to that of native speakers’ have been shown to remediate these accents, even though there is important variability across speakers in their sensitivity to training. In this study, monolingual French speakers were trained to produce the Danish /o/ vowel that is similar to the French /o/. It explores, first, the individual-specific properties of French productions in relation to L2 production before and during training. Second, it examines the effects of training with Danish /o/ on the production of similar French /o/ vowel

Second language phonological acquisition in adults: the interplay between the native and non-native languages

Speakers who acquire a foreign language (L2) in adolescence or later often experience difficulties in the production of non-native sounds. Their L2 speech is easily identified by native speakers as having a foreign accent. This thesis focuses on second-language learners' production difficulties. It attempts, first, to understand the causes of these difficulties with a particular attention paid to L2 perception and native (L1) production. Second, it tests the effectiveness of a new visual articulatory-feedback training method that aimed at enabling L2 speakers to improve their L2 pronunciation. Last, it explores the interaction between the production of native and non-native sounds. In particular, it examines the role of within- and between-speaker variability in L1 production in predicting L2 production and perception performance, and it assesses the effects of learning to produce non-native sounds on L1 production