perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
        LANGUAGE = "en_US:en",
        LC_ALL = (unset),
        LC_MESSAGES = "en_US.UTF-8",
        LANG = "en_US.UTF-8"
    are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").
locale: Cannot set LC_CTYPE to default locale: No such file or directory
locale: Cannot set LC_MESSAGES to default locale: No such file or directory
locale: Cannot set LC_ALL to default locale: No such file or directory
(Reading database ... 21173 files and directories currently installed.)
Removing bind9 ...
 * Stopping domain name service... bind9                                                                                [ OK ]
Processing triggers for man-db ...
locale: Cannot set LC_CTYPE to default locale: No such file or directory
locale: Cannot set LC_MESSAGES to default locale: No such file or directory
locale: Cannot set LC_ALL to default locale: No such file or directory

$ locale
LANG=C
LANGUAGE=
LC_CTYPE=fi_FI.UTF-8
LC_NUMERIC="C"
LC_TIME="C"
LC_COLLATE=fi_FI.UTF-8
LC_MONETARY="C"
LC_MESSAGES=fi_FI.UTF-8
LC_PAPER="C"
LC_NAME="C"
LC_ADDRESS="C"
LC_TELEPHONE="C"
LC_MEASUREMENT="C"
LC_IDENTIFICATION="C"
LC_ALL=

$ sudo locale-gen fi_FI.UTF-8
Generating locales...
  fi_FI.UTF-8... done
Generation complete.

$ sudo dpkg-reconfigure locales
Generating locales...
  en_US.UTF-8... done
  fi_FI.UTF-8... up-to-date
Generation complete.

LC_ALL=en_US.UTF-8
LANG=en_US.UTF-8

sudo locale-gen en_US en_US.UTF-8
dpkg-reconfigure locales

export LC_ALL="en_US.UTF-8"

apt-get install language-pack-en-base

export LANGUAGE=ru_RU.UTF-8
export LC_CTYPE=ru_RU.UTF-8
export LC_NUMERIC=ru_RU.UTF-8
export LC_TIME=ru_RU.UTF-8
export LC_COLLATE=ru_RU.UTF-8
export LC_MONETARY=ru_RU.UTF-8
export LC_MESSAGES=ru_RU.UTF-8
export LC_PAPER=ru_RU.UTF-8
export LC_NAME=ru_RU.UTF-8
export LC_ADDRESS=ru_RU.UTF-8
export LC_TELEPHONE=ru_RU.UTF-8
export LC_MEASUREMENT=ru_RU.UTF-8
export LC_IDENTIFICATION=ru_RU.UTF-8
export LC_ALL=ru_RU.UTF-8

export LC_ALL="en_ZA.UTF-8"
export LC_CTYPE="en_ZA.UTF-8"

$ cat ~/.kde/env/setlocale.sh
export LANG=en_US.UTF-8
export LANGUAGE=en_US:ru:en

sudo update-locale LC_ALL=en_US.UTF-8 LANG=en_US.UTF-8