This page indicates how to install / use Debian in your local language.

See :

Configuration

    *  Edit the file /etc/locale.gen and add your locale settings (one set per line), e.g.:

de_DE ISO-8859-1 de_DE@euro ISO-8859-15

**export LANG=de_DE **export LC_ALL=de_DE **export LC_CTYPE=de_DE

Zones, languages and countries