Detecting Latin in Historical Books with Large Language Models: A Multimodal Benchmark
Summary
The paper addresses a gap in historical NLP: finding Latin passages embedded in mostly English 18th-century books. These books often have noisy scans, imperfect OCR and complex layouts. The authors frame this as a two-step task. First, a system decides whether a page contains any Latin. Second, it extracts the Latin spans as text. Systems can use the page image, the OCR text, or both.
To support the task, they built a multimodal benchmark of 724 pages drawn from ECCO. Specialists annotated it, and each Latin segment is labelled with one or more of 12 usage categories, such as quotations, footnotes and code-switching. They then evaluated contemporary LLMs and multimodal LLMs in a zero-shot setting. For fair cross-modal comparison, they added an OCR post-correction and normalization step.
The main finding is that detection is highly reliable, but the models seem to depend on surface cues like vocabulary rather than real understanding of Latin. This matters for tracking the decline of Latin at scale, and image-only models could make un-OCRed archives searchable.
Key points
- Dataset construction: The benchmark contains 724 annotated pages, 594 of which contain Latin. The authors sampled 800 cross-language text-reuse cases from the Reception Reader database over ECCO (about 200,000 books), using one page per book.
- Annotation process: Three Latin-literate annotators drew bounding boxes in Label Studio, and a historical-text expert then reviewed all annotations. The boxes were mapped to text offsets through ECCO's OCR coordinates.
- Usage categories: The typology has 12 categories. The most frequent are Direct Quote (258 pages), Independent (196) and Footnote (191). The pages also contain French, German and Greek, which adds difficulty.
- Results: Image-only models reached roughly 99% page-level F1. Using raw ECCO OCR instead of corrected text cut text-only model scores by more than 14 points.
- Error analysis and resources: Most errors come from labelling Roman names, anglicized Latin phrases and Latin-derived jargon as Latin. The dataset and code are released at github.com/COMHIS/EACL26-detect-latin, and the authors plan to extend the work to all of ECCO and to BnF collections.
Cite
@inproceedings{wu2026detecting,
title = {{Detecting Latin in Historical Books with Large Language Models: A Multimodal Benchmark}},
author = {Wu, Yu and Shu, Ke and Fischer, Jonas and Pivovarova, Lidia and Rosson, David and Mäkelä, Eetu and Tolonen, Mikko},
booktitle = {Proceedings of the 19th Conference of the European Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)},
year = {2026},
doi = {10.18653/v1/2026.eacl-long.245},
url = {https://doi.org/10.18653/v1/2026.eacl-long.245}
}References
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