DaPT: A Dual-Path Framework for Multilingual Multi-hop Question Answering

TL;DR

This paper introduces DaPT, a novel dual-path multilingual RAG framework for multi-hop question answering, addressing the lack of benchmarks and improving performance in multilingual scenarios.

Contribution

DaPT is the first to generate parallel sub-question graphs for multilingual multi-hop QA, merging them for bilingual retrieval and answer generation, and it outperforms existing baselines.

Findings

DaPT improves MuSiQue benchmark EM score by 18.3%.

Multilingual RAG systems show significant performance imbalance.

DaPT achieves more accurate and concise answers.

Abstract

Retrieval-augmented generation (RAG) systems have made significant progress in solving complex multi-hop question answering (QA) tasks in the English scenario. However, RAG systems inevitably face the application scenario of retrieving across multilingual corpora and queries, leaving several open challenges. The first one involves the absence of benchmarks that assess RAG systems' capabilities under the multilingual multi-hop (MM-hop) QA setting. The second centers on the overreliance on LLMs' strong semantic understanding in English, which diminishes effectiveness in multilingual scenarios. To address these challenges, we first construct multilingual multi-hop QA benchmarks by translating English-only benchmarks into five languages, and then we propose DaPT, a novel multilingual RAG framework. DaPT generates sub-question graphs in parallel for both the source-language query and its English translation counterpart, then merges them before employing a bilingual retrieval-and-answer strategy to sequentially solve sub-questions. Our experimental results demonstrate that advanced RAG systems suffer from a significant performance imbalance in multilingual scenarios. Furthermore, our proposed method consistently yields more accurate and concise answers compared to the baselines, significantly enhancing RAG performance on this task. For instance, on the most challenging MuSiQue benchmark, DaPT achieves a relative improvement of 18.3\% in average EM score over the strongest baseline.