Programm 80. StuTS

The development of the early vocabulary is a central question when investigating language acquisition. As pointed out by previous research, semantic and phonological neighbourhood density play an important role when determining which words are acquired first. Effects were found to be larger than those caused by well-studied psycholinguistic variables such as word length.
However, there is an ongoing disagreement about the role of overlapping neighbourhoods: Is a target word with many neighbours that are similar in sound and meaning learnt earlier? For a highly normative sample of school children and college students, Cassani and Limacher, 2022 found earlier acquisition for those systematic words supposing a preferential acquisition scenario of vocabulary growth. Neighbourhoods were computed in relation to all the words in the input a child receives (EXT-like growth).
I challenge their results by employing a new calculation method for word systematicity introduced by Stich et al., 2026. The method is based on a preferential attachment scenario for vocabulary growth (INT-like growth): Systematicity values are computed in relation to all other words known by the child. An impeding effect on word acquisition was revealed for longitudinal
CDI data of Norwegian-speaking children between 18 and 36 months old.
When including an interaction of word systematicity and word frequency in my statistical analysis, no significant effect was detected which I argue is due to the small size of the child-directed speech corpus I used.

Cassani, G., & Limacher, N. (2022). Not just form, not just meaning: Words with consistent form-
meaning mappings are learned earlier. Quarterly Journal of Expermental Psychology, 75(8), 1464-1482.
Stich, F., Mundry, R., & Mani, N. (2026, April). Investigating the influence of form-meaning
systematicity on early vocabulary development [Preprint]. Retrieved July 21, 2026, from
https://osf.io/rxuc9.