OpenLID-v3: Improving the Precision of Closely Related Language Identification -- An Experience Report
2026-02-13 • Computation and Language
Computation and Language
AI summaryⓘ
The authors improved an existing language identification tool called OpenLID to better recognize closely related languages and filter out non-language noise, especially for low-resource languages. They added more training data, combined similar language variants, and created a special label for noise, naming the updated tool OpenLID-v3. They tested OpenLID-v3 against another tool, GlotLID, using new datasets they developed for certain closely related language groups. Their work shows that combining different models can increase accuracy but may reduce the amount of data identified for less common languages.
Language Identification (LID)Multilingual DatasetsLow-Resource LanguagesTraining DataLanguage VariantsNoise FilteringModel EnsembleBenchmarkingOpenLIDGlotLID
Authors
Mariia Fedorova, Nikolay Arefyev, Maja Buljan, Jindřich Helcl, Stephan Oepen, Egil Rønningstad, Yves Scherrer
Abstract
Language identification (LID) is an essential step in building high-quality multilingual datasets from web data. Existing LID tools (such as OpenLID or GlotLID) often struggle to identify closely related languages and to distinguish valid natural language from noise, which contaminates language-specific subsets, especially for low-resource languages. In this work we extend the OpenLID classifier by adding more training data, merging problematic language variant clusters, and introducing a special label for marking noise. We call this extended system OpenLID-v3 and evaluate it against GlotLID on multiple benchmarks. During development, we focus on three groups of closely related languages (Bosnian, Croatian, and Serbian; Romance varieties of Northern Italy and Southern France; and Scandinavian languages) and contribute new evaluation datasets where existing ones are inadequate. We find that ensemble approaches improve precision but also substantially reduce coverage for low-resource languages. OpenLID-v3 is available on https://huggingface.co/HPLT/OpenLID-v3.