I logged in gnome-shell, and found that the display language is set to some strange asian language (I think) without my prompt. I tried to change the locale settings but found that the default language is English (how?) despite of that strange language. Here's a snapshot, See the strange word instead of "Activity": I'm on Ubuntu 12.04 LTS. Output of locale: LANG=zh_CN.UTF-8 LANGUAGE=zh_CN:en_US:en LC_CTYPE="zh_CN.UTF-8" LC_NUMERIC=en_US.UTF-8 LC_TIME=en_US.UTF-8 LC_COLLATE="zh_CN.UTF-8" LC_MONETARY=en_US.UTF-8 LC_MESSAGES="zh_CN.UTF-8" LC_PAPER=en_US.UTF-8 LC_NAME=en_US.UTF-8 LC_ADDRESS=en_US.UTF-8 LC_TELEPHONE=en_US.UTF-8 LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=en_US.UTF-8 LC_ALL= Output of locale -a: C C.UTF-8 de_CH.utf8 en_AG en_AG.utf8 en_AU.utf8 en_BW.utf8 en_CA.utf8 en_DK.utf8 en_GB.utf8 en_IE.utf8 en_IN en_IN.utf8 en_NG en_NG.utf8 en_NZ.utf8 en_PH.utf8 en_SG.utf8 en_US.utf8 en_ZA.utf8 en_ZM en_ZM.utf8 en_ZW.utf8 POSIX zh_CN.utf8 zh_SG.utf8 Solved: This answer did it.