$ sudo apt-get update
$ sudo apt-get install fcitx-frontend-all 

fcitx-frontend-all is installed in your system.

Make ensure the fcitx-frontend-all package were installed using the commands given below,

$ sudo dpkg-query -l | grep fcitx-frontend-all *

You will get with fcitx-frontend-all package name, version, architecture and description in a table

fcitx-frontend-all package basic information: