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arXiv 2510.27254cs.CLcs.AIcs.LG

语言即模态:通过编码器注入实现跨语言对齐

Languages are Modalities: Cross-Lingual Alignment via Encoder Injection

University of Waterloo(多伦多大学)

Rajan Agarwal, Aarush Gupta

AI总结:

针对LLM在低资源非拉丁语种上表现不佳的问题,提出LLINK方法,通过轻量级对比投影器将冻结多语言编码器的句子嵌入注入解码器,无需重训解码器即可显著提升跨语言对齐与问答性能。

摘要:

由于分词器碎片化和较弱的跨语言耦合,经过指令微调的大型语言模型(LLMs)在低资源、非拉丁字母语种上表现不佳。我们提出了 LLINK(Latent Language Injection for Non-English Knowledge,面向非英语知识的潜在语言注入),这是一种计算高效的“语言即模态”方法,它在不改变分词器或重新训练解码器的情况下对指令微调解码器进行条件化。首先,我们通过轻量级对比投影器,将来自冻结多语言编码器的句子嵌入在预留位置对齐到解码器的潜在嵌入空间。其次,该向量被扩展为 K 个软槽,并使用最少的适配器进行训练,以便冻结的解码器能够消耗该信号。LLINK 显著提升了双语检索能力,并在 LLM 评判的问答评估中,相比基础模型获得了 81.3% 的偏好度,相比直接微调获得了 63.6% 的偏好度。我们进一步发现,尽管模型在数值保真度上存在残余弱点,但这些改进可归因于分词膨胀的减少和更强的跨语言对齐。将低资源语言视为一种模态,为轻量级 LLM 实现更强的跨语言对齐提供了一条实用路径。

英文摘要:

Instruction-tuned Large Language Models (LLMs) underperform on low resource, non-Latin scripts due to tokenizer fragmentation and weak cross-lingual coupling. We present LLINK (Latent Language Injection for Non-English Knowledge), a compute efficient language-as-modality method that conditions an instruction-tuned decoder without changing the tokenizer or retraining the decoder. First, we align sentence embeddings from a frozen multilingual encoder to the decoder's latent embedding space at a reserved position via a lightweight contrastive projector. Second, the vector is expanded into K soft slots and trained with minimal adapters so the frozen decoder consumes the signal. LLINK substantially improves bilingual retrieval and achieves 81.3% preference over the base model and 63.6% over direct fine-tuning in LLM-judged Q&A evaluations. We further find that improvements can be attributed to reduced tokenization inflation and a stronger cross lingual alignment, despite the model having residual weaknesses in numeric fidelity. Treating low resource languages as a modality offers a practical path to stronger cross-lingual alignment in lightweight LLMs.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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