Tracing Syntactic Complexity: Exploring the Evolution of Average Dependency Length Across Three Centuries of Scientific English

What it is about

The question is whether average dependency length (aDL) per sentence, which earlier work found to fall, keeps falling in scientific English. The authors extend the Royal Society Corpus to cover 1665 to 1996, with about 129 million tokens, and parse it with Stanza into UD. The average falls until the 19th century and then rises significantly in the 20th century. A fine-grained analysis points to multi-word compounds as the main source of long leftward noun phrases. On a manually corrected sample of 140 sentences, the parser reaches a UAS of 91.06 overall. Counting compounds as single words changes the aDL figures visibly.

Ideas

• I1. en ud-eval: report aDL per sentence on EWT test twice, once with multi-word compounds counted as MWEs and once as single words. The paper shows that this choice shifts the curve.
• I2. en/src/ctx.rs: use aDL as a genre signal for multi-pass parsing, with values measured on EWT, on GUM test (test only) and on plain school text, and check whether the genre split changes the parse.
• I3. Hand-checked sample: draft a 100-sentence sample of our own text with two annotators, as the paper's 140-sentence check does, and report en parse-eval UAS and LAS on it.

For Mova

The code is en/src/ctx.rs and the command en ud-eval; the chapters are 18. Compounding, conversion and the minor processes and 21-clause-structure.md. The paper's parser is Stanza, not en. The Royal Society Corpus is not in our licence list, so no text from it enters the build.

Cite

The paper itself, not this card. BibTeX from the library's record of the work.

@inproceedings{krielke2025tracing,
  title = {{Tracing Syntactic Complexity: Exploring the Evolution of Average Dependency Length Across Three Centuries of Scientific English}},
  author = {Krielke, Marie-Pauline and Alves, Diego and Talamo, Luigi},
  booktitle = {Proceedings of the Eighth International Conference on Dependency Linguistics (Depling, SyntaxFest 2025)},
  year = {2025},
  url = {https://aclanthology.org/2025.depling-1.2/}
}

References

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