A Feature-Fusion Ensemble Approach for Tamil Hate Speech Detection

Sathasivam Nerujan, Kengatharaiyer Sarveswaran


Abstract
Detecting online toxicity in morphologically rich, low-resource languages like Tamil remains a major computational challenge. Standard transformer models often struggle with sub-word fragmentation, which can dilute the semantic intensity of regional insults and out-of-vocabulary slang. To mitigate this limitation, we train a multi-layer hybrid framework that fuses the deep contextual representations of L3Cube-TamilBERT with the character-level robustness of FastText embeddings. Our architecture leverages Last-4 Layers averaging and a dual pooling strategy (Mean + Max) to capture both global sentence intent and extract high-activation spikes of offensive cues typically lost in single layer representations. Experiments show that this hybrid model achieves a Macro-F1 of 0.7883, notably enhancing Hate Recall (0.7503) for detection of offensive content. Additionally, as reported by other studies, stacking ensemble achieves peak hate precision (0.9296), providing a high accuracy alternative for moderation scenarios requiring minimal false positives. By combining deep contextual hidden states with FastText embeddings, the proposed feature-fusion ensemble approach with multi-layer hybrid framework approach establishes a new benchmark for hate speech detection for Tamil.
Anthology ID:
2026.chipsal-1.18
Volume:
Proceedings of the Second workshop on Challenges in Processing South Asian Languages (CHiPSAL2026)
Month:
May
Year:
2026
Address:
Palma de Mallorca, Spain
Editors:
Kengatharaiyer Sarveswaran, Ashwini Vaidya
Venues:
CHiPSAL | WS
SIG:
Publisher:
ELRA Language Resources Association (ELRA)
Note:
Pages:
190–197
Language:
External URL:
https://lrec.elra.info/lrec2026-ws-chipsal-18
DOI:
10.63317/2us8ubrf4jvi
Bibkey:
Cite (ACL):
Sathasivam Nerujan and Kengatharaiyer Sarveswaran. 2026. A Feature-Fusion Ensemble Approach for Tamil Hate Speech Detection. In Proceedings of the Second workshop on Challenges in Processing South Asian Languages (CHiPSAL2026), pages 190–197, Palma de Mallorca, Spain. ELRA Language Resources Association (ELRA).
Cite (Informal):
A Feature-Fusion Ensemble Approach for Tamil Hate Speech Detection (Nerujan & Sarveswaran, CHiPSAL 2026)
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