arXiv AI
Sep 2

The Interlingua Hypothesis: LLMs Translate via a Latent Task-agnostic Feature Space

The paper proposes the interlingua hypothesis, suggesting that large language models translate by encoding a source sentence into a latent, task‑agnostic feature space and then decoding a target sentence from that space. Three lines of evidence support this: (1) BLEU variance across language pairs is largely explained by language‑specific competences without pair‑specific interactions; (2) many model components influence both monolingual and translation tasks; and (3) fine‑tuning on monolingual data recovers most translation gains seen with aligned documents. These findings converge to support the hypothesis and point toward new ways to understand and improve LLM translation.

By Jacob Brinton, Jannik Brinkmann, Mark Crovella, Aaron Mueller
arXiv Computation and Language
Aug 28

Cross-lingual Representation Learning via Centroid Intervention Fusion

The paper introduces Centroid Intervention Fusion (CIF), a framework that merges multiple multilingual intervention projections into a single language-shared operator for inference-time modification of large language models. CIF improves cross-lingual transfer without updating model parameters and achieves up to +3.378 percentage points better performance than prior pairwise intervention baselines across several benchmarks, including low-resource languages. The authors provide code at https://github.com/VRCMF/CIF.git.

By Wei Sun, Marie-Francine Moens
arXiv AI
Sep 7

A Systematic Evaluation of Cross-Lingual Consistency Enhancement Methods in Multilingual Language Models

The paper presents a unified evaluation of cross‑lingual consistency (CLC) enhancement methods for multilingual language models, covering inference‑time interventions and post‑training approaches across three model families and three closed‑form benchmarks. Results indicate that post‑training methods, especially direct distribution alignment, consistently improve CLC across all model‑dataset combinations, while other methods are more sensitive to answer format and language coverage. The study also examines the impact of CLC enhancement on culturally diverse question answering, finding no systematic degradation in controlled settings but occasional accuracy drops in open‑ended generation, particularly for non‑English responses.

By Jirui Qi, Mingyang Wang, Hinrich Sch\"utze, Raquel Fern\'andez, Arianna Bisazza
arXiv Computation and Language
Sep 1

Beyond the Final Layer: Intermediate Representations for Better Multilingual Calibration in Large Language Models

The paper investigates multilingual confidence calibration in large language models, revealing that non‑English languages are systematically less well calibrated than English. By analyzing internal representations, the authors find that late‑intermediate layers provide a more reliable confidence signal than the final layer, which is biased by English‑centric training. They propose training‑free methods such as Language‑Aware Confidence Ensemble (LACE) to adaptively select optimal layers per language, aiming to improve global equity and trustworthiness of LLMs.

By Ej Zhou, Caiqi Zhang, Tiancheng Hu, Chengzu Li, Nigel Collier, Ivan Vuli\'c, Anna Korhonen