collaborators

8 papers

cs.CL2026

Scaling Unsupervised Word Alignment to Documents via Structural Constraints

Michelle Wastl, Jannis Vamvas, Rico Sennrich

Word alignment has traditionally been studied between sentences, but many cross-lingual tasks increasingly require correspondences across full documents. While recent multilingual…

cs.CL2026

Reinforcement Learning Elicits Contextual Learning of Unseen Language Translation

Hanxu Hu, Zdeněk Šnajdr, Pinzhen Chen +2

Prior work has shown that large language models (LLMs) can translate unseen or low-resource languages by undergoing continued training or even by encoding a grammar book in their c…

cs.CL2026

Translation Asymmetry in LLMs as a Data Augmentation Factor: A Case Study for 6 Romansh Language Varieties

Jannis Vamvas, Ignacio Pérez Prat, Angela Heldstab +3

Recent strategies for low-resource machine translation rely on LLMs to generate synthetic data from higher-resource languages. We find that this method fails for Romansh, because L…

cs.CL2026

DeReason: A Difficulty-Aware Curriculum Improves Decoupled SFT-then-RL Training for General Reasoning

Hanxu Hu, Yuxuan Wang, Maggie Huan +4

Reinforcement learning with Verifiable Rewards (RLVR) has emerged as a powerful paradigm for eliciting reasoning capabilities in large language models, particularly in mathematics…

cs.CL2025

Apertus: Democratizing Open and Compliant LLMs for Global Language Environments

Project Apertus, Alejandro Hernández-Cano, Alexander Hägele +100

We present Apertus, a fully open suite of large language models (LLMs) designed to address two systemic shortcomings in today's open model ecosystem: data compliance and multilingu…

cs.CL2025

Expanding the WMT24++ Benchmark with Rumantsch Grischun, Sursilvan, Sutsilvan, Surmiran, Puter, and Vallader

Jannis Vamvas, Ignacio Pérez Prat, Not Battesta Soliva +14

The Romansh language, spoken in Switzerland, has limited resources for machine translation evaluation. In this paper, we present a benchmark for six varieties of Romansh: Rumantsch…