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arXiv 2510.07613cs.CLcs.AI
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词汇嵌入在语言模型训练早期组织语言结构

Vocabulary embeddings organize linguistic structure early in language model training

University of British Columbia(不列颠哥伦比亚大学);Harvard University(哈佛大学)

Isabel Papadimitriou, Jacob Prince

AI总结:

本研究通过表征相似性分析,发现语言模型训练早期词汇嵌入几何结构快速收敛于语义和句法特征,高频和功能词收敛更快,揭示了词汇组织动态及其对能力提升的启示。

摘要:

大型语言模型(LLMs)通过多层操作输入嵌入向量的几何结构来工作。在此,我们提出疑问:语言模型的输入词汇表示是如何结构的,这种结构在训练过程中如何以及何时演变?为回答此问题,我们使用表征相似性分析,运行一系列实验,将两个开源模型(Pythia 12B和OLMo 7B)的输入嵌入和输出嵌入的几何结构与语义、句法和基于频率的指标在训练过程中进行关联。我们的主要发现如下:1)在训练期间,词汇嵌入几何结构迅速收敛到与一系列语义和句法特征的高相关性;2)高频词和功能词(如“the”,“of”)的嵌入比词汇词和低频词更快地收敛到其最终向量,后者保留了与其随机初始化中的偏差的一定对齐。这些发现有助于描绘输入嵌入围绕语言结构组织的动态轨迹,揭示了词频和功能的不同作用。我们的发现激发了对词汇几何演变如何在模型训练中促进特定能力提升的更深入研究。

英文摘要:

Large language models (LLMs) work by manipulating the geometry of input embedding vectors over multiple layers. Here, we ask: how are the input vocabulary representations of language models structured, and how and when does this structure evolve over training? To answer this question, we use representational similarity analysis, running a suite of experiments that correlate the geometric structure of the input embeddings and output embeddings of two open-source models (Pythia 12B and OLMo 7B) with semantic, syntactic, and frequency-based metrics over the course of training. Our key findings are as follows: 1) During training, the vocabulary embedding geometry quickly converges to high correlations with a suite of semantic and syntactic features; 2) Embeddings of high-frequency and function words (e.g., "the," "of") converge to their final vectors faster than lexical and low-frequency words, which retain some alignment with the bias in their random initializations. These findings help map the dynamic trajectory by which input embeddings organize around linguistic structure, revealing distinct roles for word frequency and function. Our findings motivate a deeper study of how the evolution of vocabulary geometry may facilitate specific capability gains during model training.

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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