Improving Language Identification for Code-Switched Utterances with Integer Linear Programming

Joanna Radoła, Josep Crego, François Yvon


Abstract
Automatic identification of code-switched (CS) utterances remains a challenge for language identification (LID) systems, causing such texts to be underrepresented in the training data of Large Language Models. In this paper, we revisit MaskLID, a state-of-the art approach for CS identification, which requires no training and detects arbitrary language combinations. We make three main contributions: (a) we reveal, and address, a major issue of MaskLID: its overreliance on word-level language association scores; (b) we reformulate the underlying optimization algorithm as an Integer Linear Program, enabling us to experiment with a large set of clear and interpretable constraints; (c) each of these improvements vastly improves the baseline system, as we illustrate in experiments involving 10 diverse languages, where we observe a strong boost in performance on CS benchmarks.
Anthology ID:
2026.findings-emnlp.1429
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
30450–30468
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.1429/
DOI:
Bibkey:
Cite (ACL):
Joanna Radoła, Josep Crego, and François Yvon. 2026. Improving Language Identification for Code-Switched Utterances with Integer Linear Programming. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 30450–30468, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Improving Language Identification for Code-Switched Utterances with Integer Linear Programming (Radoła et al., Findings 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.findings-emnlp.1429.pdf