Beyond Decoder-only: Large Language Models Can be Good Encoders for
  Machine Translation
Authors: name: Yingfeng Luo; name: Tong Zheng; name: Yongyu Mu; name: Bei Li; name: Qinghong Zhang; name: Yongqi Gao; name: Ziqiang Xu; name: Peinan Feng; name: Xiaoqian Liu; name: Tong Xiao; name: Jingbo Zhu
Published: 2025-03-09 12:54:05

Abstract: The field of neural machine translation (NMT) has changed with the advent of
large language models (LLMs). Much of the recent emphasis in natural language
processing (NLP) has been on modeling machine translation and many other
problems using a single pre-trained Transformer decoder, while encoder-decoder
architectures, which were the standard in earlier NMT models, have received
relatively less attention. In this paper, we explore translation models that
are universal, efficient, and easy to optimize, by marrying the world of LLMs
with the world of NMT. We apply LLMs to NMT encoding and leave the NMT decoder
unchanged. We also develop methods for adapting LLMs to work better with the
NMT decoder. Furthermore, we construct a new dataset involving multiple tasks
to assess how well the machine translation system generalizes across various
tasks. Evaluations on the WMT and our datasets show that results using our
method match or surpass a range of baselines in terms of translation quality,
but achieve 2.4 sim 6.5 times inference speedups and a 75% reduction in
the memory footprint of the KV cache. It also demonstrates strong
generalization across a variety of translation-related tasks.