If you are a chinese writer, or you want to use chinese input under english locale ( default locale ). Usually people uses either scim or fcitx, or maybe gcin. Fcitx Installation how to, can check out here.
If you have scim or fcitx installed, and you want to make either one of them become your default input, im-switch come to help. im-switch is a bash script, make sure you have that installed.
To list all input method configuration.
To change your default input to scim.
im-switch -s scim
P.S. Relogin to see the effects.
To allow you to set input method specifically to a locale, example locale en_US
im-switch -z en_US -s scim
To allow you to choose which input to configure