RETUYT-INCO at BEA 2026 Shared Task 1: Feature-Enriched mDeBERTa for Word Difficulty Prediction
Summary
RETUYT-INCO participated in the BEA 2026 Shared Task 1, focusing on Vocabulary Difficulty Prediction for English Learners. This regression task involved predicting GLMM psychometric difficulty scores for English words, given L1 cues in Spanish, German, or Mandarin. They submitted two systems to the closed track: a feature-engineered XGBoost regressor for all L1s, and a 3-seed mdeberta-v3-base ensemble for Spanish, enhanced with handcrafted features. Their best result was 1.094 RMSE on Spanish, a 13.0% reduction over the XLM-RoBERTa-base baseline. A LaBSE cross-lingual cosine feature significantly reduced development RMSE by 0.091. Notably, the feature-only XGBoost, without neural fine-tuning or GPU, outperformed the XLM-RoBERTa-base development baseline with 1.273 RMSE versus 1.287 RMSE.
Key takeaway
For Machine Learning Engineers developing cross-lingual NLP systems, you should prioritize robust feature engineering, especially incorporating cross-lingual embeddings like LaBSE. Your team can achieve competitive performance with simpler models like XGBoost, even without GPUs, potentially outperforming larger neural baselines. Consider prepending handcrafted features directly into transformer inputs to boost fine-tuning effectiveness.
Key insights
Feature engineering and cross-lingual embeddings significantly enhance word difficulty prediction, even outperforming complex neural baselines.
Principles
- Handcrafted features boost neural model performance.
- Cross-lingual embeddings are powerful for L1-L2 similarity.
- Simpler models can be highly competitive.
Method
The approach involved fine-tuning mDeBERTa-v3-base with prepended handcrafted features and utilizing a feature-engineered XGBoost regressor for word difficulty prediction.
In practice
- Integrate LaBSE cross-lingual cosine for L1-L2 tasks.
- Evaluate XGBoost for strong, efficient baselines.
- Prepend features as input tokens for mDeBERTa fine-tuning.
Topics
- Vocabulary Difficulty Prediction
- mDeBERTa-v3-base
- XGBoost
- Feature Engineering
- Cross-lingual Embeddings
- BEA Shared Task
Best for: AI Engineer, Research Scientist, AI Scientist, Machine Learning Engineer, NLP Engineer
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Editorial summary, takeaway, and curation by AIssential. Original article published by Paper Index on ACL Anthology.