Languages not included in the distribution package may be added at a later time. Please check the translation status page to see whether your preferred language is available already, and to download the message catalogue.
To update a language, download the appropriate .mo file, and update your local copy. This is normally stored under /usr/share/pgadmin3/i18n/lc_CC on Linux and other Unixes or C:\Program Files\pgAdmin III\X.Y\i18n\lc_CC on Windows, where lc_CC is your language code and country code - e.g. pt_BR for Portuguese as spoken in Brazil
To add a new language, follow the update procedure, but create the lc_CC directory if required and save the new message catalogue in it. You may also need to update the i18n/pgadmin3.lng file which is also available from the translation status page.