I have been teaching in Higher Education since 2003.

I mainly teach courses in child language development and neurolinguistics, but also in research methodology, experimental design, project and thesis courses, both in English and Swedish.

I am interested in how children develop language in interaction with their environment, using cognitive neuroscience methods. My focus lies on early language development during infancy, toddlerhood and the preschool years, and how this process manifests in the brain. I study infant- and child-directed speech, parent-child interaction and the neural basis of speech perception and turn-taking in adults and infants. 

Language is a core cognitive ability that sets the path for children's later development on many levels. That is why I work to identify factors that promote children's language development and advocate language-building interaction strategies for families and preschool staff. 

A selection from Stockholm University publication database

• The development of tone discrimination in infancy: Evidence from a cross‐linguistic, multi‐lab report

  2024. Marina Kalashnikova (et al.). Developmental Science 27 (3)

  Article

  We report the findings of a multi-language and multi-lab investigation of young infants’ ability to discriminate lexical tones as a function of their native language, age and language experience, as well as of tone properties. Given the high prevalence of lexical tones across human languages, understanding lexical tone acquisition is fundamental for comprehensive theories of language learning. While there are some similarities between the developmental course of lexical tone perception and that of vowels and consonants, findings for lexical tones tend to vary greatly across different laboratories. To reconcile these differences and to assess the developmental trajectory of native and non-native perception of tone contrasts, this study employed a single experimental paradigm with the same two pairs of Cantonese tone contrasts (perceptually similar vs. distinct) across 13 laboratories in Asia-Pacific, Europe and North-America testing 5-, 10- and 17-month-old monolingual (tone, pitch-accent, non-tone) and bilingual (tone/non-tone, non-tone/non-tone) infants. Across the age range and language backgrounds, infants who were not exposed to Cantonese showed robust discrimination of the two non-native lexical tone contrasts. Contrary to this overall finding, the statistical model assessing native discrimination by Cantonese-learning infants failed to yield significant effects. These findings indicate that lexical tone sensitivity is maintained from 5 to 17 months in infants acquiring tone and non-tone languages, challenging the generalisability of the existing theoretical accounts of perceptual narrowing in the first months of life.

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• Affect in Infant-Directed Speech of Swedish-Speaking Mothers and Fathers to 3-, 6-, 9-, and 12-Month-Old Infants

  2024. Iris-Corinna Schwarz (et al.). Language Learning and Development 20 (2), 145-157

  Article

  Infant-directed speech (IDS) is characterized by a range of register-typical characteristics. Many of those can be objectively measured, such as acoustic-prosodic and structural-linguistic modifications. Perceived vocal affect, however, is a socio-emotional IDS characteristic and is subjectively assessed. Vocal affect goes beyond acoustic-prosodic and structural-linguistic IDS features and includes a perceptive-subjective component in the listener. This study describes vocal affect valence in Swedish IDS during the first year of life, and compares vocal affect between mothers’ and fathers’ IDS and their adult-directed speech. Adult native speakers of Swedish (N = 16) rated affect valence in low-pass filtered IDS samples from free play interactions of mothers with infants at 3, 6, 9, and 12 months (N = 10) and fathers with their 12-month-olds (N = 6). Across the first year, the trajectory of mothers’ positive affect in Swedish IDS shows the highest affect scores toward the youngest infants and the lowest at 9 months of age. This follows a pattern comparable to that in Australian English IDS, showing that mothers express vocal affect similarly across different languages and cultures. Both mothers’ and fathers’ IDS to 12-month-olds have higher positive vocal affect valence than their adult-directed speech. There was no difference in positive affect valence between mothers’ and fathers’ IDS, that is, mothers and fathers express vocal affect to the same extent when talking to their infants. In conclusion, the findings of this study indicate that high positive vocal affect characterizes IDS across different languages and speakers.

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• Developmental trajectories of non-native tone perception differ between monolingual and bilingual infants learning a pitch accent language

  2024. Liquan Liu (et al.). Infant Behavior and Development 77

  Article

  The developmental trajectories of tone perception among tone and non-tone language learning infants have received wide attention and discussion in recent decades under the perceptual attunement framework. Nevertheless, tone perception in infants from pitch accent and bilingual language backgrounds has not been well understood. The present study examined monolingual and bilingual Norwegian-learning infants’ discrimination of two Cantonese tone contrasts at 5 and 10 months, ages corresponding to the onset and offset of perceptual attunement. Results showed that while monolingual infants were sensitive to the salient contrast, bilingual infants showed sensitivity to both contrasts at 10 months. In sum, infant age and bilingual language background affected discrimination. Pitch accent language experience or contrast salience may also play a role. The finding that early bilingual experience facilitated tone perception is of particular interest. It suggests that infant perception could be enhanced by a more complex linguistic environment on a broader level. As this was observed only at 10 months, cumulative exposure may be required for infants in a complex bilingual environment. Future studies should disambiguate explanations generated from the current finding, ranging from neurocognitive plasticity to perceptual salience, and from experience-dependent to independent possibilities.

  Read more about Developmental trajectories of non-native tone perception differ between monolingual and bilingual infants learning a pitch accent language

• Everyday language input and production in 1,001 children from six continents

  2023. Elika Bergelson (et al.). Proceedings of the National Academy of Sciences of the United States of America 120 (52)

  Article

  Language is a universal human ability, acquired readily by young children, who otherwise struggle with many basics of survival. And yet, language ability is variable across individuals. Naturalistic and experimental observations suggest that children’s linguistic skills vary with factors like socioeconomic status and children’s gender. But which factors really influence children’s day-to-day language use? Here, we leverage speech technology in a big-data approach to report on a unique cross-cultural and diverse data set: >2,500 d-long, child-centered audio-recordings of 1,001 2- to 48-mo-olds from 12 countries spanning six continents across urban, farmer-forager, and subsistence-farming contexts. As expected, age and language-relevant clinical risks and diagnoses predicted how much speech (and speech-like vocalization) children produced. Critically, so too did adult talk in children’s environments: Children who heard more talk from adults produced more speech. In contrast to previous conclusions based on more limited sampling methods and a different set of language proxies, socioeconomic status (operationalized as maternal education) was not significantly associated with children’s productions over the first 4y of life, and neither were gender or multilingualism. These findings from large-scale naturalistic data advance our understanding of which factors are robust predictors of variability in the speech behaviors of young learners in a wide range of everyday contexts.

  Read more about Everyday language input and production in 1,001 children from six continents

• Amount of speech exposure predicts vowel perception in four- to eight-month-olds

  2019. Ellen Marklund, Iris-Corinna Schwarz, Francisco Lacerda. Developmental Cognitive Neuroscience 36

  Article

  During the first year of life, infants shift their focus in speech perception from acoustic to linguistic information. This perceptual reorganization is related to exposure, and a direct relation has previously been demonstrated between amount of daily language exposure and mismatch response (MMR) amplitude to a native consonant contrast at around one year of age. The present study investigates the same relation between amount of speech exposure and MMR amplitude to a native vowel contrast at four to eight months of age. Importantly, the present study uses spectrally rotated speech in an effort to take general neural maturation into account. The amplitude of the part of the MMR that is tied specifically to speech processing correlates with amount of daily speech exposure, as estimated using the LENA system.

  Read more about Amount of speech exposure predicts vowel perception in four- to eight-month-olds

• Pause and utterance duration in child-directed speech in relation to child vocabulary size

  2015. Ulrika Marklund (et al.). Journal of Child Language 42 (5), 1158-1171

  Article

  This study compares parental pause and utterance duration in conversations with Swedish speaking children at age 1;6 who have either a large, typical, or small expressive vocabulary, as measured by the Swedish version of the McArthur-Bates CDI. The adjustments that parents do when they speak to children are similar across all three vocabulary groups; they use longer utterances than when speaking to adults, and respond faster to children than they do to other adults. However, overall pause duration varies with the vocabulary size of the children, and as a result durational aspects of the language environment to which the children are exposed differ between groups. Parents of children in the large vocabulary size group respond faster to child utterances than do parents of children in the typical vocabulary size group, who in turn respond faster to child utterances than do parents of children in the small vocabulary size group.

  Read more about Pause and utterance duration in child-directed speech in relation to child vocabulary size

Show all publications by Iris-Corinna Schwarz at Stockholm University