Beyond English-Centric LLMs: What Language Do Multilingual Language Models Think in?

Fuente: arXiv
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Main Authors: Zhong, Chengzhi, Cheng, Fei, Liu, Qianying, Jiang, Junfeng, Wan, Zhen, Chu, Chenhui, Murawaki, Yugo, Kurohashi, Sadao
Format: Preprint
Published: 2024
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author Zhong, Chengzhi
Cheng, Fei
Liu, Qianying
Jiang, Junfeng
Wan, Zhen
Chu, Chenhui
Murawaki, Yugo
Kurohashi, Sadao
author_facet Zhong, Chengzhi
Cheng, Fei
Liu, Qianying
Jiang, Junfeng
Wan, Zhen
Chu, Chenhui
Murawaki, Yugo
Kurohashi, Sadao
contents In this study, we investigate whether non-English-centric LLMs, despite their strong performance, `think' in their respective dominant language: more precisely, `think' refers to how the representations of intermediate layers, when un-embedded into the vocabulary space, exhibit higher probabilities for certain dominant languages during generation. We term such languages as internal $\textbf{latent languages}$. We examine the latent language of three typical categories of models for Japanese processing: Llama2, an English-centric model; Swallow, an English-centric model with continued pre-training in Japanese; and LLM-jp, a model pre-trained on balanced English and Japanese corpora. Our empirical findings reveal that, unlike Llama2 which relies exclusively on English as the internal latent language, Japanese-specific Swallow and LLM-jp employ both Japanese and English, exhibiting dual internal latent languages. For any given target language, the model preferentially activates the latent language most closely related to it. In addition, we explore how intermediate layers respond to questions involving cultural conflicts between latent internal and target output languages. We further explore how the language identity shifts across layers while keeping consistent semantic meaning reflected in the intermediate layer representations. This study deepens the understanding of non-English-centric large language models, highlighting the intricate dynamics of language representation within their intermediate layers.
format Preprint
id arxiv_https___arxiv_org_abs_2408_10811
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Beyond English-Centric LLMs: What Language Do Multilingual Language Models Think in?
Zhong, Chengzhi
Cheng, Fei
Liu, Qianying
Jiang, Junfeng
Wan, Zhen
Chu, Chenhui
Murawaki, Yugo
Kurohashi, Sadao
Computation and Language
Artificial Intelligence
In this study, we investigate whether non-English-centric LLMs, despite their strong performance, `think' in their respective dominant language: more precisely, `think' refers to how the representations of intermediate layers, when un-embedded into the vocabulary space, exhibit higher probabilities for certain dominant languages during generation. We term such languages as internal $\textbf{latent languages}$. We examine the latent language of three typical categories of models for Japanese processing: Llama2, an English-centric model; Swallow, an English-centric model with continued pre-training in Japanese; and LLM-jp, a model pre-trained on balanced English and Japanese corpora. Our empirical findings reveal that, unlike Llama2 which relies exclusively on English as the internal latent language, Japanese-specific Swallow and LLM-jp employ both Japanese and English, exhibiting dual internal latent languages. For any given target language, the model preferentially activates the latent language most closely related to it. In addition, we explore how intermediate layers respond to questions involving cultural conflicts between latent internal and target output languages. We further explore how the language identity shifts across layers while keeping consistent semantic meaning reflected in the intermediate layer representations. This study deepens the understanding of non-English-centric large language models, highlighting the intricate dynamics of language representation within their intermediate layers.
title Beyond English-Centric LLMs: What Language Do Multilingual Language Models Think in?
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2408.10811