What confuses BERT? Linguistic Evaluation of Sentiment Analysis on Telecom Customer Opinion. - Cing-Fang Shih; Yu-Hsiang Tseng; Ching-Wen Yang; Pin-Er Chen; Hsin-Yu Chou; Lian-Hui Tan; Tzu-Ju Lin; Chun-Wei Wang; Shu-Kai Hsieh (ROCLING, 2021)