Dolphin: A Spoken Language Proficiency Assessment System for Elementary Education. - Zitao Liu 001; Guowei Xu; Tianqiao Liu; Weiping Fu; Yubi Qi; Wenbiao Ding; Yujia Song; Chaoyou Guo; Cong Kong; Songfan Yang; Gale Yan Huang (WWW, 2020)