@inproceedings{vishwakarma-kumar-2026-low,
title = "Why Does Low-Rank Adaptation Work for {H}indi-{E}nglish Code-Mixing? A Geometric Analysis",
author = "Vishwakarma, Shashank and
Kumar, Rakesh",
editor = "Sarveswaran, Kengatharaiyer and
Vaidya, Ashwini",
booktitle = "Proceedings of the Second workshop on Challenges in Processing {S}outh {A}sian Languages ({CH}i{PSAL}2026)",
month = may,
year = "2026",
address = "Palma de Mallorca, Spain",
publisher = "ELRA Language Resources Association (ELRA)",
url = "https://aclanthology.org/2026.chipsal-1.13/",
doi = "10.63317/55yuuwkijgj9",
pages = "127--136",
abstract = "Low-Rank Adaptation (LoRA) enables efficient fine-tuning of large language models, yet why it works particularly well for code-mixed text remains unexplained. We propose that LoRA{'}s efficiency stems from geometric structure in multilingual pre-trained models: code-mixed embeddings concentrate in low-dimensional cross-lingual subspaces. Through spectral analysis of mBERT and MuRIL on Hindi-English (Hinglish) data, we establish that pre-trained attention weights have effective ranks of 437{--}441, while LoRA updates (r = 4,8,16) exhibit ranks of 2.1{--}5.9{---}a 136{\texttimes} average compression. Cross-lingual geometry measured via Centered Kernel Alignment shows Hinglish embeddings align strongly with Hindi (CKA=0.279) but weakly with English (0.093), compared to a monolingual baseline of 0.074. Statistical tests (Wilcoxon p {\ensuremath{<}} 10{\ensuremath{-}}19) and permutation ablations confirm these differences are robust. We interpret the convergence of geometric overlap (3.77{\texttimes} baseline) and empirical compression (136{\texttimes}) as evidence that low-rank adaptation exploits pre-existing multilingual structure. Findings are demonstrated on token-level language identification; extensions to other language pairs and tasks remain open questions."
}<?xml version="1.0" encoding="UTF-8"?>
<modsCollection xmlns="http://www.loc.gov/mods/v3">
<mods ID="vishwakarma-kumar-2026-low">
<titleInfo>
<title>Why Does Low-Rank Adaptation Work for Hindi-English Code-Mixing? A Geometric Analysis</title>
</titleInfo>
<name type="personal">
<namePart type="given">Shashank</namePart>
<namePart type="family">Vishwakarma</namePart>
<role>
<roleTerm authority="marcrelator" type="text">author</roleTerm>
</role>
</name>
<name type="personal">
<namePart type="given">Rakesh</namePart>
<namePart type="family">Kumar</namePart>
<role>
<roleTerm authority="marcrelator" type="text">author</roleTerm>
</role>
</name>
<originInfo>
<dateIssued>2026-05</dateIssued>
</originInfo>
<typeOfResource>text</typeOfResource>
<relatedItem type="host">
<titleInfo>
<title>Proceedings of the Second workshop on Challenges in Processing South Asian Languages (CHiPSAL2026)</title>
</titleInfo>
<name type="personal">
<namePart type="given">Kengatharaiyer</namePart>
<namePart type="family">Sarveswaran</namePart>
<role>
<roleTerm authority="marcrelator" type="text">editor</roleTerm>
</role>
</name>
<name type="personal">
<namePart type="given">Ashwini</namePart>
<namePart type="family">Vaidya</namePart>
<role>
<roleTerm authority="marcrelator" type="text">editor</roleTerm>
</role>
</name>
<originInfo>
<publisher>ELRA Language Resources Association (ELRA)</publisher>
<place>
<placeTerm type="text">Palma de Mallorca, Spain</placeTerm>
</place>
</originInfo>
<genre authority="marcgt">conference publication</genre>
</relatedItem>
<abstract>Low-Rank Adaptation (LoRA) enables efficient fine-tuning of large language models, yet why it works particularly well for code-mixed text remains unexplained. We propose that LoRA’s efficiency stems from geometric structure in multilingual pre-trained models: code-mixed embeddings concentrate in low-dimensional cross-lingual subspaces. Through spectral analysis of mBERT and MuRIL on Hindi-English (Hinglish) data, we establish that pre-trained attention weights have effective ranks of 437–441, while LoRA updates (r = 4,8,16) exhibit ranks of 2.1–5.9—a 136× average compression. Cross-lingual geometry measured via Centered Kernel Alignment shows Hinglish embeddings align strongly with Hindi (CKA=0.279) but weakly with English (0.093), compared to a monolingual baseline of 0.074. Statistical tests (Wilcoxon p \ensuremath< 10\ensuremath-19) and permutation ablations confirm these differences are robust. We interpret the convergence of geometric overlap (3.77× baseline) and empirical compression (136×) as evidence that low-rank adaptation exploits pre-existing multilingual structure. Findings are demonstrated on token-level language identification; extensions to other language pairs and tasks remain open questions.</abstract>
<identifier type="citekey">vishwakarma-kumar-2026-low</identifier>
<identifier type="doi">10.63317/55yuuwkijgj9</identifier>
<location>
<url>https://aclanthology.org/2026.chipsal-1.13/</url>
</location>
<part>
<date>2026-05</date>
<extent unit="page">
<start>127</start>
<end>136</end>
</extent>
</part>
</mods>
</modsCollection>
%0 Conference Proceedings
%T Why Does Low-Rank Adaptation Work for Hindi-English Code-Mixing? A Geometric Analysis
%A Vishwakarma, Shashank
%A Kumar, Rakesh
%Y Sarveswaran, Kengatharaiyer
%Y Vaidya, Ashwini
%S Proceedings of the Second workshop on Challenges in Processing South Asian Languages (CHiPSAL2026)
%D 2026
%8 May
%I ELRA Language Resources Association (ELRA)
%C Palma de Mallorca, Spain
%F vishwakarma-kumar-2026-low
%X Low-Rank Adaptation (LoRA) enables efficient fine-tuning of large language models, yet why it works particularly well for code-mixed text remains unexplained. We propose that LoRA’s efficiency stems from geometric structure in multilingual pre-trained models: code-mixed embeddings concentrate in low-dimensional cross-lingual subspaces. Through spectral analysis of mBERT and MuRIL on Hindi-English (Hinglish) data, we establish that pre-trained attention weights have effective ranks of 437–441, while LoRA updates (r = 4,8,16) exhibit ranks of 2.1–5.9—a 136× average compression. Cross-lingual geometry measured via Centered Kernel Alignment shows Hinglish embeddings align strongly with Hindi (CKA=0.279) but weakly with English (0.093), compared to a monolingual baseline of 0.074. Statistical tests (Wilcoxon p \ensuremath< 10\ensuremath-19) and permutation ablations confirm these differences are robust. We interpret the convergence of geometric overlap (3.77× baseline) and empirical compression (136×) as evidence that low-rank adaptation exploits pre-existing multilingual structure. Findings are demonstrated on token-level language identification; extensions to other language pairs and tasks remain open questions.
%R 10.63317/55yuuwkijgj9
%U https://aclanthology.org/2026.chipsal-1.13/
%U https://doi.org/10.63317/55yuuwkijgj9
%P 127-136
Markdown (Informal)
[Why Does Low-Rank Adaptation Work for Hindi-English Code-Mixing? A Geometric Analysis](https://aclanthology.org/2026.chipsal-1.13/) (Vishwakarma & Kumar, CHiPSAL 2026)
ACL