arXiv Computation and Language
Aug 28

STAR : Sentence Translation Alignment Rate for Document-to-Document Machine Translation

The paper introduces STAR, a metric that measures sentence-level alignment between source and target documents in document-to-document machine translation. Using STAR, the authors develop StarPO, a preference‑optimization framework that ranks translation hypotheses by structural quality and applies a dynamic alignment mask to focus learning on misaligned segments. Experiments on news and literary data show that StarPO improves both translation quality and structural integrity, enabling small models to outperform large proprietary systems such as GPT‑4o while remaining more token‑efficient.

By Yichen Dong, Hao Wang, Junhui Li, Linlong Xu, Longyue Wang, Weihua Luo
arXiv Computation and Language
Aug 28

Cross-Lingual Alignment Without Joint Training: Do Monolingual Language Models Converge on Universal Representations?

The study investigates whether monolingual language models, trained without joint multilingual objectives, develop cross-lingual alignment. By evaluating models such as Goldfish and independently built monolingual systems, the authors find that alignable representational geometry emerges across layers, strengthening with larger data, larger models, or closer linguistic proximity. A single Procrustes rotation on parallel sentences can map hidden states between models, and applying this rotation to a German model’s residuals swaps factual predictions to those of the donor English model, demonstrating functional transfer.

By Ej Zhou, Suchir Salhan, Catherine Arnett, Anna Korhonen
arXiv Computation and Language
Sep 14

Doc2FRC: Length-Consistent Document-Level Machine Translation via Fixed-Range Chunking

Doc2FRC introduces Fixed-Range Chunking (FRC), a dynamic programming method that partitions documents into chunks of a predefined length interval, ensuring consistent length distributions during training and inference. This approach reduces train-test length mismatch, mitigates n-gram repetition, and improves translation quality for 7B LLMs compared to direct Doc2Doc fine-tuning. Experiments on IWSLT2017 and a new 10-language test set, GlobVDoc, demonstrate that FRC outperforms existing document-level machine translation methods and enhances out-of-distribution translation performance.

By Xiaotian Wang, Youyuan Lin, Zhan Shen, Hitomi Yanaka
arXiv AI
Oct 2

Cross-Lingual Alignment for Decoder-Only Models using MoE Routers

The paper introduces a new method for aligning cross‑lingual representations in decoder‑only large language models by leveraging the outputs of mixture‑of‑experts (MoE) routers instead of traditional hidden‑state alignment losses. This approach pools router outputs over many tokens, providing more reliable sequence‑level comparisons across languages. Experiments on four open‑source MoEs show that the routing loss not only aligns hidden representations but also improves multilingual performance across a diverse evaluation suite.

By Lucas Bandarkar, Clark Peng, Ahmed Haj Ahmed, Aditi Khandelwal, Nanyun Peng