Our submission to Nature Materials, "Sub-unit-cell-segmented ferroelectricity in brownmillerite oxides by phonon decoupling" authored by Jinhyuk Jang, Yeongrok Jin, Yeon-Seo Nam, Heung-Sik Park, Jaegyu Kim, Kyeong Tae Kang, Yerin So, Jiwoung Choi, Youngchang Choi, Jaechan Shim, Panithan Sriboriboon, Dong Kyu Lee, Kyoung-June Go, Gi-Yeop Kim, Seungbum Hong, Jun Hee Lee, Daesu Lee, Myung-Geun Han, Junwoo Son, Yunseok Kim, Hiroki Taniguchi, Seokhyeong Kang, Jang-Sik Lee, He Tian, Chan-Ho Yang, Yimei Zhu, Sang-Wook Cheong, Woo Seok Choi, Jaekwang Lee and Si-Young Choi has been accepted.