What Language(s) Does Aya-23 Think In? How Multilinguality Affects Internal Language Representations

Fuente: arXiv
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Autores principales: Trinley, Katharina, Nakai, Toshiki, Anikina, Tatiana, Baeumel, Tanja
Formato: Preprint
Publicado: 2025
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author Trinley, Katharina
Nakai, Toshiki
Anikina, Tatiana
Baeumel, Tanja
author_facet Trinley, Katharina
Nakai, Toshiki
Anikina, Tatiana
Baeumel, Tanja
contents Large language models (LLMs) excel at multilingual tasks, yet their internal language processing remains poorly understood. We analyze how Aya-23-8B, a decoder-only LLM trained on balanced multilingual data, handles code-mixed, cloze, and translation tasks compared to predominantly monolingual models like Llama 3 and Chinese-LLaMA-2. Using logit lens and neuron specialization analyses, we find: (1) Aya-23 activates typologically related language representations during translation, unlike English-centric models that rely on a single pivot language; (2) code-mixed neuron activation patterns vary with mixing rates and are shaped more by the base language than the mixed-in one; and (3) Aya-23's languagespecific neurons for code-mixed inputs concentrate in final layers, diverging from prior findings on decoder-only models. Neuron overlap analysis further shows that script similarity and typological relations impact processing across model types. These findings reveal how multilingual training shapes LLM internals and inform future cross-lingual transfer research.
format Preprint
id arxiv_https___arxiv_org_abs_2507_20279
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle What Language(s) Does Aya-23 Think In? How Multilinguality Affects Internal Language Representations
Trinley, Katharina
Nakai, Toshiki
Anikina, Tatiana
Baeumel, Tanja
Computation and Language
Large language models (LLMs) excel at multilingual tasks, yet their internal language processing remains poorly understood. We analyze how Aya-23-8B, a decoder-only LLM trained on balanced multilingual data, handles code-mixed, cloze, and translation tasks compared to predominantly monolingual models like Llama 3 and Chinese-LLaMA-2. Using logit lens and neuron specialization analyses, we find: (1) Aya-23 activates typologically related language representations during translation, unlike English-centric models that rely on a single pivot language; (2) code-mixed neuron activation patterns vary with mixing rates and are shaped more by the base language than the mixed-in one; and (3) Aya-23's languagespecific neurons for code-mixed inputs concentrate in final layers, diverging from prior findings on decoder-only models. Neuron overlap analysis further shows that script similarity and typological relations impact processing across model types. These findings reveal how multilingual training shapes LLM internals and inform future cross-lingual transfer research.
title What Language(s) Does Aya-23 Think In? How Multilinguality Affects Internal Language Representations
topic Computation and Language
url https://arxiv.org/abs/2507.20279