Sailor2: Sailing in South-East Asia with Inclusive Multilingual LLMs
Authors: name: Longxu Dou, name: Qian Liu, name: Fan Zhou, name: Changyu Chen, name: Zili Wang, name: Ziqi Jin, name: Zichen Liu, name: Tongyao Zhu, name: Cunxiao Du, name: Penghui Yang, name: Haonan Wang, name: Jiaheng Liu, name: Yongchi Zhao, name: Xiachong Feng, name: Xin Mao, name: Man Tsung Yeung, name: Kunat Pipatanakul, name: Fajri Koto, name: Min Si Thu, name: Hynek Kydlíček, name: Zeyi Liu, name: Qunshu Lin, name: Sittipong Sripaisarnmongkol, name: Kridtaphad Sae-Khow, name: Nirattisai Thongchim, name: Taechawat Konkaew, name: Narong Borijindargoon, name: Anh Dao, name: Matichon Maneegard, name: Phakphum Artkaew, name: Zheng-Xin Yong, name: Quan Nguyen, name: Wannaphong Phatthiyaphaibun, name: Hoang H. Tran, name: Mike Zhang, name: Shiqi Chen, name: Tianyu Pang, name: Chao Du, name: Xinyi Wan, name: Wei Lu, name: Min Lin
Organization: Sea AI Lab

Sailor2 is a family of cutting-edge multilingual language models for
South-East Asian (SEA) languages, available in 1B, 8B, and 20B sizes to suit
diverse applications. Building on Qwen2.5, Sailor2 undergoes continuous
pre-training on 500B tokens (400B SEA-specific and 100B replay tokens) to
support 13 SEA languages while retaining proficiency in Chinese and English.
Sailor2-20B model achieves a 50-50 win rate against GPT-4o across SEA
languages. We also deliver a comprehensive cookbook on how to develop the
multilingual model in an efficient manner, including five key aspects: data
curation, pre-training, post-training, model customization and evaluation. We
hope that Sailor2 model (Apache 2.0 license) will drive language development in
the SEA region, and Sailor2 cookbook will inspire researchers to build more
inclusive LLMs for other under-served languages.