Lexilogic@IWSLT 2026: Pairwise Ranking Fine-tuning of CometKiwi for Speech Translation Quality Estimation

Pranav Gupta


Abstract
We describe our submission to the IWSLT 2026 Speech Translation Metrics Shared Task for the ASR text to translated text evaluation scenario. We fine-tune CometKiwi-22, a 580M-parameter quality estimation model, with a pair-wise ranking objective, and construct within-document translation pairs and train with an adaptive margin ranking loss combined with mean squared error (MSE) calibration. Our system achieves 35.2% per-source Kendall’s τ on the dev (development) set.
Anthology ID:
2026.iwslt-1.38
Volume:
Proceedings of the 23rd International Conference on Spoken Language Translation (IWSLT 2026)
Month:
July
Year:
2026
Address:
San Diego, USA (in-person and online)
Editors:
Elizabeth Salesky, Antonios Anastasopoulos, Matteo Negri, Marcello Federico
Venues:
IWSLT | WS
SIG:
SIGSLT
Publisher:
Association for Computational Linguistics
Note:
Pages:
332–335
Language:
URL:
https://aclanthology.org/2026.iwslt-1.38/
DOI:
Bibkey:
Cite (ACL):
Pranav Gupta. 2026. Lexilogic@IWSLT 2026: Pairwise Ranking Fine-tuning of CometKiwi for Speech Translation Quality Estimation. In Proceedings of the 23rd International Conference on Spoken Language Translation (IWSLT 2026), pages 332–335, San Diego, USA (in-person and online). Association for Computational Linguistics.
Cite (Informal):
Lexilogic@IWSLT 2026: Pairwise Ranking Fine-tuning of CometKiwi for Speech Translation Quality Estimation (Gupta, IWSLT 2026)
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PDF:
https://aclanthology.org/2026.iwslt-1.38.pdf