With the advent of large language models, machine translation (MT) has become a widely used, but little understood, tool for accessing historical and multilingual texts. While models like GPT, Claude, and Deepseek increasingly enable translation of low-resource and ancient languages, critical questions remain about their evaluation, optimal model selection, and the value of domain-specific training and retrieval-augmented generation setups.While AI models like GPT, Claude, and Deepseek are improving translation capabilities for low-resource and ancient languages, researchers still face important questions about how to evaluate their performance, which models work best, and whether specialized training approaches provide meaningful improvements in translation quality.This study introduces a comprehensive evaluation dataset for Buddhist Chinese to English translation, comprising 2,662 bilingual data points from 32 texts that have been selected to represent the full breadth of the Chinese Buddhist canon.We evaluate various computational metrics of translation quality (BLEU, chrF, BLEURT, GEMBA) against expert annotations from five domain specialists who rated 182 machine-generated translations. Our analysis reveals that LLM-based GEMBA scoring shows the strongest correlation with human judgment, significantly outperforming traditional metrics. We then benchmark commercial models (GPT-4 Turbo, Claude 3.5, Gemini), open-source models (Gemma 2, Deepseek-r1), and a domain-specialized model (Gemma 2 Mitra) using GEMBA. Our results demonstrate that domain-specific training enables open-weights models to achieve competitive performance with commercial systems, while also showing that retrieval-augmented generation (RAG) significantly improves translation quality for the best performing commercial models.

Buddhist Classical Chinese is a challenging low-resource language that has not yet received much dedicated attention in NLP research. Standard commercial machine translation software performs poorly on this idiom. In order to address this gap, we present a novel dataset of 209,454 bitext pairs for the training and 2.300 manually curated and corrected bitext pairs for the evaluation of machine translation models. We finetune a number of encoder-decoder models on this dataset and compare their performance against commercial models. We show that our best fine-tuned model outperforms the currently available commercial solutions by a considerable margin while being much more cost-efficient and faster in deployment. This is especially important for digital humanities, where large amounts of data need to be processed efficiently for corpus-level operations such as topic modeling or semantic search. We also show that the commercial chat system GPT4 is surprisingly strong on this task, at times reaching comparable performance to our finetuned model and clearly outperforming standard machine translation providers. We provide a limited case study where we examine the performance of selected different machine translation models on a number of Buddhist Chinese passages in order to demonstrate what level of quality these models reach at the moment.