Parsing the Switch: LLM-Based UD Annotation for Complex Code-Switched and Low-Resource Languages
Summary
The paper tackles syntactic annotation of code-switched text, where monolingual parsers generalise poorly and annotated data hardly exists. It introduces the BiLingua Pipeline: an LLM (GPT-4.1) is prompted with few-shot examples and a set of linguistic rules to produce UD part-of-speech tags, heads and relations, after which experts and native speakers review and correct the output. The pipeline is applied to Spanish-English conversational data from the Miami Corpus and to Spanish-Guaraní social-media and news text, yielding two released datasets, including the first UD corpus for Spanish-Guaraní. After expert revision the annotation reaches up to 95.29% LAS, well above earlier baselines and multilingual parsers. The authors also propose a more lenient evaluation that does not penalise linguistically acceptable alternatives, and analyse at which syntactic positions speakers switch languages. The overall message is that a carefully guided LLM plus human review can bootstrap syntactic resources for low-resource, mixed-language settings.
How Mova uses it
- dep — only as a last resort — cited as a source of the rule
en.errors.dep-last-resort: LLM annotators fall back todepon repetitions, ellipsis and contractions (the paper's prompt even alloweddepfor ellipsis), so everydepis flagged for review in EWT style. - Typical failures of LLM annotators for UD — failure mode 5 ("inconsistency"): human correction raised LAS from about 76 to 95, which Mova reads as a warning that the yardstick must be an independent gold standard, not corrected LLM output.
- VP ellipsis: the auxiliary becomes the head — background for the rule
en.errors.aux-before-verb(LLMs are inconsistent on ellipsis).
Effectiveness in Mova
The paper informs one warning rule and the catalogue of LLM-annotator failure modes used when Mova's deterministic annotator is checked against LLM drafts. Not measured separately.
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Cite
@inproceedings{kellert2025parsing,
title = {{Parsing the Switch: LLM-Based UD Annotation for Complex Code-Switched and Low-Resource Languages}},
author = {Kellert, Olga and Tyagi, Nemika and Imran, Muhammad and Licona-Guevara, Nelvin and Gómez-Rodríguez, Carlos},
booktitle = {Findings of the Association for Computational Linguistics: EMNLP 2025},
year = {2025},
doi = {10.18653/v1/2025.findings-emnlp.863},
eprint = {2506.07274},
archivePrefix = {arXiv},
url = {https://doi.org/10.18653/v1/2025.findings-emnlp.863}
}References
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