DoyouunderstandwhatIamsaying? How learners break into speech segmentation

In my Habilitation project, I study the mechanisms available to FL- and L2 learners to parse incoming speech into individual words, how the input can be modified to ease learning, and how we can improve learning situations and educational approaches for L2 and FL learning. One strain focuses on the role of individual differences. This is best exemplified in German Research Foundation funded grant that I am co-PI (216,325 €) on with Prof. Holger Hopp Ini-Seg: Initial foreign speech segmentation in school-aged children. Ini-Seg examines how individual differences in early language and cognitive abilities support initial processing and learning from a FL before instruction in that FL has begun. Within this project I am mentoring a PhD student (Marie Schnieders) and a postdoctoral researcher (Sophia Wulfert).

A second strain studies how features of the speech input encourage or hinder learning. When we speak with language learners, we modify our speech, whether we are addressing infants (infant-directed speech, IDS) or adults (foreigner-directed speech, FDS), but we know little of whether these modifications support uptake in FL and L2 learners. I have mentored several bachelors’ (Pauls; Tekin) and masters’ (Heimann; Lumpe) students within this project, as well as a current PhD student (Flohr), and have presented preliminary findings at conferences (Von Holzen, 2022b, 2022a), finding a clear advantage for IDS, but intermediate findings for FDS that require further study. Input can also be modified to highlight similarities between the FL or L2 and the learners’ first language(s) (L1), which can support initial word recognition in a foreign language (Von Holzen, Fennell, & Mani, 2019; Von Holzen & Newman, 2021). Together with bachelors’ students, I collected preliminary evidence of the role of L2 proficiency in the use of the specific properties of the L2 (phonotactics) to segment speech, but also how they may be hampered in this process by conflicting cues from their L1 (Von Holzen, Harnischmacher, & Schuster, 2021).

Please read more about the Ini-Seg project here.

Open and Collaborative approaches to language acquisition Research

I study early language and cognitive development using a global, collaborative, open science approach. As a member of the leadership committee of the ManyBabies-AtHome project, I work to reduce the WEIRD (Western, Educated, Industrialized, Rich, Democratic) bias by both building a resource-friendly and accessible, open-source toolkit for online eye-tracking experiments as well as establishing a research network to study diverse study populations (Von Holzen, Bergmann, & ManyBabies-AtHome-Consortium, 2022a; Von Holzen & ManyBabies-AtHome-Consortium, 2022). In the Looking-While-Listening sub-project, I manage a diverse team of international researchers as we design a massively cross-linguistic experiment (10+ languages) to study word recognition over the second year of life (Von Holzen, Bergmann, & ManyBabies-AtHome-Consortium, 2022b). I also contributed to the first ManyBabies initiative (ManyBabiesConsortium, 2020) and am a collaborator in Many Babies 5, which examines the Hunter and Ames model of infant looking preference (Kosie, Zettersten, & The ManyBabies5 Team, under review). I firmly believe that such global, collaborative approaches are essential for the field of early language development.

My study investigating simultaneous acitvation in bilingual toddlers (Von Holzen & Mani, 2012) was the first to apply a non-parametic permutation clusters analysis in the language acquisition field, where my role was adapting the analysis to my own data and subsequently promoting this analysis with other language acquisition researchers (see my Tutorials). This analysis captures important differences in the timing of effects across a time course while controlling for the false-alarm rate.

In completing the meta-analysis of mispronunciation sensitivity development, my role was tabulating over two decades of research and analyzing the results with meta-analytic models. This provides an essential integration of research on mispronunciation sensitivity in early language acquisition and gives future researchers the tools to plan their own mispronunciation sensitivity studies. This meta-analysis with my co-author, Christina Bergmann, is published in Developmental Psychology (Von Holzen & Bergmann, 2021). A preprint and the open data and code can be found here.

The Role of Consonants and Vowels in Lexical Processing

During lexical processing, more weight is often given to consonants than vowels. This pattern has been found in adult speakers of all languages tested thus far, leading to the proposal that humans have a bias for consonants during lexical prosessing (C-bias). Cross-linguistic and developmental evidence suggests that this C-bias may be acquired through early linguistic experience (Nazzi, Poltrock, & Von Holzen, 2016). My postdoctoral work focused on the acoustic/phonetic and lexical factors that drive this emergence during early language acquisition in French-learning infants. Our findings favor an interpretation of C-bias emergence guided by acoustic/phonetic factors, but show that early sensitivity to both consonants and vowels is related to general lexical development over the first two years of life (Von Holzen & Nazzi, 2020; Von Holzen, Nishibayashi, & Nazzi, 2018; Von Holzen, van Ommen, White, & Nazzi, 2022).

The Nature of Bilingual Lexical Processing Across the Lifespan

Bilinguals must often navigate a linguistic environment that requires them to use only one of their languages. Yet, evidence of connections between the bilingual’s two languages suggest that lexical entries from the other language are active and ready to be accessed, even when the language itself is not currently being used. My dissertation work and subsequent work extends previous findings with evidence that even when completing a task in their first language (L1), bilingual adults activate the labels for objects in both of their languages (Bobb, Von Holzen, Mayor, Mani, & Carreiras, 2020; Von Holzen & Mani, 2014). I also demonstrated that young bilingual toddlers also activate both languages simultaneously, providing the first evidence of this phenomenon in bilingual children this young (Von Holzen & Mani, 2012). These bilingual toddlers are also sensitive to the phonological overlap between their two languages, which impacts their word recognition (Von Holzen et al., 2019). The results suggest that connections between a bilingual’s two languages are evident across the lifespan. Moreover, these findings have generated considerable scientific interest: groups in several other countries are currently working to replicate and extend them.


Bobb, S. C., Von Holzen, K., Mayor, J., Mani, N., & Carreiras, M. (2020). Co-activation of the L2 during L1 auditory processing : An ERP cross-modal priming study. Brain and Language, 203, 104739.
Kosie, J., Zettersten, M., & The ManyBabies5 Team. (under review). ManyBabies5: A large-scale investigation of the proposed shift from familiarity preference to novelty preference in infant looking time.
ManyBabiesConsortium. (2020). Quantifying sources of variability in infancy research using the infant-directed speech preference. Advances in Methods and Practices in Psychological Science.
Nazzi, T., Poltrock, S., & Von Holzen, K. (2016). The developmental origins of the consonant bias in lexical processing. Current Directions in Psychological Science, 25(4), 291–296.
Von Holzen, K. (2022a). Doyouunderstandwhatimsaying : How learners break into speech stream segmentation. Presented at the HaBilNet2 Workshop, Frankfurt, Germany.
Von Holzen, K. (2022b). The role of speech modifications in ab inito learners’ initial speech segmentation. 4th International Symposium on Bilingual and L2 Processing in Adults and Children, Tromso, Norway.
Von Holzen, K., & Bergmann, C. (2021). The development of infants\('\) responses to mispronunciations: A Meta-Analysis. Developmental Psychology, 57(1), 1–18.
Von Holzen, K., Bergmann, C., & ManyBabies-AtHome-Consortium. (2022b). ManyBabies-AtHome looking while listening: Constructing an online, cross-linguistic investigation of word recognition.
Von Holzen, K., Bergmann, C., & ManyBabies-AtHome-Consortium. (2022a). ManyBabies-AtHome looking while listening: Constructing an online, cross-linguistic investigation of word recognition. Presented at the 52nd Congress of the German Psychological Society, Hildesheim, Germany.
Von Holzen, K., Fennell, C. T., & Mani, N. (2019). The impact of cross-language phonological overlap on bilingual and monolingual toddlers’ word recognition. Bilingualism: Language and Cognition.
Von Holzen, K., Harnischmacher, V., & Schuster, N. (2021). Phonetic cues in L2 speech segmentation. Presented at the 2021 Conference Architectures and Mechanisms for Language Processing (AMLap), Paris, France.
Von Holzen, K., & Mani, N. (2012). Language nonselective lexical access in bilingual toddlers. Journal of Experimental Child Psychology, 113, 569–586.
Von Holzen, K., & Mani, N. (2014). Bilinguals implicitly name objects in both their languages: An ERP study. Frontiers in Psychology, 5(DEC), 1–12.
Von Holzen, K., & ManyBabies-AtHome-Consortium. (2022). ManyBabies-AtHome. Presented at the 2022 Big Team Science Conference, Virtual Conference.
Von Holzen, K., & Nazzi, T. (2020). Emergence of a consonant bias during the first year of life: New evidence from own-name recognition. Infancy, 25(3), 319–346.
Von Holzen, K., & Newman, R. (2021). The recognition of foreign words at first exposure in early language development: The role of phonological similarity.
Von Holzen, K., Nishibayashi, L.-L., & Nazzi, T. (2018). Consonant and vowel processing in word form segmentation: An infant ERP study. Brain Sciences, 8(24), 1–15.
Von Holzen, K., van Ommen, S., White, K., & Nazzi, T. (2022). The impact of phonological biases on mispronunciation sensitivity and novel accent adaptation. Language Learning and Development.