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Transitions between discrete developmental stages during language acquisition through syntax network morphospace

Lluís Barceló-Coblijn1,2,3,*, Víctor M. Eguíluz4, and Luís F. Seoane5,†

  • *Contact author: lluis.barcelo@uib.cat
  • †Contact author: brigan@gmail.com
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Phys. Rev. Research 8, 023174 – Published 18 May, 2026

DOI: https://doi.org/10.1103/d93c-hm6w

Abstract

Syntax is an aspect of human language that sorts linguistic structures hierarchically. It is summarized by dependency trees with words as nodes and edges reflecting syntactic subordination. By merging trees from several sentences, we obtain syntax graphs or networks, which display distinct shapes depending on whether the language capability is well formed, still developing, or pathological. Such graphs make syntactic capacity quantifiable at a systemic level. What is the structure of syntax networks during ontogeny in typically developing children? Do cognitively challenged children develop language through alternative routes? We quantify and portray typical development of syntax networks in Dutch, and find that children affected by Down syndrome, hearing impairment, and specific language impairment track the typical developmental path but halt along the way. Through a broad dataset and a thorough mathematical quantification we (1) confirm and refine a proposed sharp transition in language development, (2) correlate network traits with syntax maturation, and (3) quantify aspects that fall short in atypical development—suggesting potential diagnostic tools. We find grounds to hypothesize a gap in syntax maturation that typically developing children bridge over seamlessly, but which divides atypically developing children regardless of their condition. Our quantitative analysis enables a rigorous visualization of linguistic development trajectories, an old (yet mostly qualitative) theme in linguistics. Similar works should allow to test specific linguistic concepts (such as development trajectories) on solid quantitative grounds—as done here. Future efforts should generalize to other languages and clinical conditions, seeking patterns and universalities in language development.

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Phys. Rev. Research 8, 023174– Published 18 May, 2026
  • Received 2 December 2025
  • Accepted 11 March 2026
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