Translation Analytics for Freelancers II: Benchmarking Local LLMs for Confidential Translation Workflows

Yuri Balashov, Rex Vanhorn, Mingxi Xu, Austin Downes


Abstract
Building on our previous work, this paper develops practical, low-barrier methods for freelance translators and smaller language service providers to evaluate translation technologies using rigorous yet accessible analytic methods. Here we address a high-stakes, specialized need: offline translation for confidentiality-sensitive domains in which privacy constraints preclude the use of cloud-based engines and commercial LLMs. We expand the Reeve Foundation Trilingual Corpus (RFTC) used in our previous work into a multilingual corpus (RFMC) by adding sentence-aligned German and Simplified Chinese reference translations. We then benchmark several locally runnable language models (via Ollama) across four language directions on 1000+ sentences selected from this corpus. We use consistent single-prompt calls without fine-tuning or domain adaptation, comparing local LLM outputs against commercial NMTs (DeepL, Baidu), a frontier LLM (GPT-5.2), and professional-grade local NMT systems (OPUS-CAT, NeuralDesktop, Promt). Automatic evaluation is conducted with MATEO. Results reveal substantial variation in local LLM performance across language directions and model sizes. The best local LLMs match or surpass local NMT systems and a frontier LLM, though they remain behind top commercial NMTs. These findings underscore the viability of carefully selected local LLM translation for privacy-constrained professionals and inform future research on model scaling and multilingual capability.
Anthology ID:
2026.eamt-1.37
Volume:
Proceedings of the 26th Annual Conference of the European Association for Machine Translation (Volume 1)
Month:
June
Year:
2026
Address:
Tilburg, The Netherlands
Editors:
Dimitar Shterionov, Eva Vanmassenhove, Mirella De Sisto, Fred Blain, Javad Pourmostafa Roshan Sharami, Lisa Lepp, Chiara Manna, Argentina Anna Rescigno, Alina Karakanta, Ayla Rigouts Terryn, Manuel Lardelli, Natalia Resende, Elena Murgolo, Janiça Hackenbuchner, Anna Zaretskaya, Miquel Esplà-Gomis, Thierry Etchegoyhen, Dagmar Gromann, Rachel Bawden, Barry Haddow, Sara Szoc, Mikel Forcada, Helena Moniz
Venue:
EAMT
SIG:
Publisher:
European Association for Machine Translation
Note:
Pages:
588–607
Language:
URL:
https://aclanthology.org/2026.eamt-1.37/
DOI:
Bibkey:
Cite (ACL):
Yuri Balashov, Rex Vanhorn, Mingxi Xu, and Austin Downes. 2026. Translation Analytics for Freelancers II: Benchmarking Local LLMs for Confidential Translation Workflows. In Proceedings of the 26th Annual Conference of the European Association for Machine Translation (Volume 1), pages 588–607, Tilburg, The Netherlands. European Association for Machine Translation.
Cite (Informal):
Translation Analytics for Freelancers II: Benchmarking Local LLMs for Confidential Translation Workflows (Balashov et al., EAMT 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.eamt-1.37.pdf