First make sure your library language is installed

sudo apt-get install language-pack-en-base,

for example.

Then, as superuser, shorten the work by allowing Ubuntu to automatically configure them:

sudo dpkg-reconfigure locales

Check your setup, if it‘s correct then good. But if you have the LANG= or LANGUAGE= settings blank, run this in command line:

locale -a

Which generates the locales installed and available to you.

Choose the locale from the output generated that fits your situation, and export that setting to replace your locales, for example:

export LC_ALL="en.utf-8"

For manual installation use export to set locale by hand which will manually install custom locales, first run the set up as above.

Then, say you want to install "en_us-8" for language but have need for another locale for NUMERIC and TIME, you may wish to use "en_NZ.utf-8" (remember: these are case-sensitive) or LANGUAGE="en_GB.utf-8" and NUMERIC="en.dk.ISO-8859-15". Traveling to New Zealand, I could change the locale LANGUAGE="en.NZ". For Germany, I would just need to install the locales pkg for it and input, in terminal, like the examples below:

export LC_ALL="en_US"
export LANG="en_US"
export LANGUAGE="en_NZ"
export C_CTYPE="en_US"
export LC_NUMERIC=
export LC_TIME=en"en_US"

LC_ALL= may remain empty.