arXiv:2607. 20301v1 Announce Type: new Abstract: Fine-tuning has been widely used to adapt large language models (LLMs) for domain-specific tasks.
The paper introduces Latent Space Refusal Anchoring (LSR‑Anchoring), a training‑free technique that extracts a refusal direction from English prompts and applies it to the residual stream of instruction‑tuned models at inference time. The primary variant, Mean‑Activation Steering (MAS), works across several architectures (Llama‑3‑8B, Llama‑3.1‑70B, Mistral‑7B‑Instruct, Qwen2.5‑7B), restoring safety for low‑resource African languages with minimal performance loss, while a refined SAE‑Derived Steering (SDS) further reduces KL divergence without degrading legitimate prompt performance. The method shows positive transfer for Yoruba, Igbo, Igala, and Hausa, but fails for Arabic, suggesting a geometric mismatch rather than a data scarcity issue.
The paper introduces Representation Geometry Regularization (RGR) to address capability degradation observed in On-Policy Self-distillation (OPSD) for large language models. OPSD can cause previously correct responses to become incorrect even as overall performance rises, a problem linked to deteriorating hidden representation geometry—specifically, less compact intra-cluster and weaker inter-cluster separation. RGR preserves this geometry by encouraging cluster compactness and separation during post‑training, and can be added to existing OPSD methods without changing their core optimization, with experiments showing it mitigates degradation while maintaining improvements.
The study evaluates how different input representations—orthographic text, IPA transcription, and romanization—affect cross‑lingual transfer in autoregressive multilingual language models. Across three model sizes and eight languages grouped into typologically motivated pairs, romanized pretraining consistently outperforms native orthography and IPA, especially as model scale increases. Fine‑tuning a text‑pretrained model on romanized data can harm performance on languages already covered by the base model, suggesting romanization should be integrated at pretraining rather than applied later.
Pixel language models treat text as rendered images, enabling strong cross‑lingual transfer. This study trains MPIXEL models varying languages, scripts, and capacity while keeping per‑language compute constant, and evaluates them on five tasks across 83 languages. Results show that scaling improves performance on added languages and scripts, mitigates the curse of multilinguality, and outperforms subword and character baselines on typologically distant low‑resource languages, though transfer to unseen scripts does not benefit further from scaling.
arXiv:2605. 02608v2 Announce Type: replace-cross Abstract: Transformer-based models achieve state-of-the-art dependency parsing for high-resource languages, yet their advantage over simpler architectures in low-resource settings remains poorly understood.
The paper addresses training instabilities in large language model pretraining, specifically output logit divergence that occurs near the end of training. By analyzing the geometry of output embeddings, the authors identify anisotropic embeddings as the root cause and propose Output Embedding Centering (OEC) as a mitigation strategy. OEC can be applied deterministically as μ‑centering or as a regularization loss μ‑loss, and experiments show both variants outperform the existing z‑loss method while matching logit soft‑capping in stability, even without weight tying. Additionally, μ‑loss is less sensitive to hyperparameter tuning than z‑loss.
arXiv:2608. 07629v1 Announce Type: cross Abstract: Multilingual neural machine translation models such as NLLB-200 cover 200 languages but leave thousands unsupported, including most Grassfields Bantu languages of Cameroon.
Large language models show strong cross‑lingual abilities, but previous studies have examined them only at isolated training points. This work pretrains a 1.7B multilingual model on nine languages, recording checkpoints at fine granularity to track translation development. Using word‑level translation and a new dataset, the authors find that early learning is dominated by token‑level copying and surface similarities, while later stages involve more general translation mechanisms and refined copying.
arXiv:2606. 06888v1 Announce Type: new Abstract: Classical scaling laws for language model pretraining balance model size against training dataset size under a fixed compute budget, assuming abundant data and a single pass over the corpus.
The study demonstrates that large language models can be compressed by clustering weight matrices into only 16–64 shared values without retraining, preserving strong accuracy. Fine‑tuning the cluster centroids recovers most of the remaining accuracy loss. Analysis reveals that maintaining the relative rank of weights and their overall variance is crucial for performance, while early layers and spatial geometry of cluster assignments also play significant roles.
Dialectal variation remains a major challenge for multilingual language models. Perturbation-based continued pre-training (CPT) has emerged as a promising approach to improving robustness, yet existing work largely evaluates individual perturbation strategies in isolation and provides limited insight into why they work.