If you want to find out if your language is already present in QGIS or who is currently working on your language you have to take a look in the Help -> About -> Translators Box in the QGIS Desktop Application.
You will also find the progress of the translation there (but remember in every “stable” version it will always stay at the same level). For finding the current percentage of translation you will either have to install the nightly build of QGIS or checkout the source code of QGIS and start translating there.
If you plan to contribute to an existing language or you want to translate the QGIS GUI into a not yet existing language and for any other related questions, please contact the Translation Team Leader (see Organigram) or subscribe with the qgis-gui-translation-team mailing list.
After subscribing to the mailing list you are able to send a mail directly to firstname.lastname@example.org asking for help.
We strongly encourage anyone dealing with translations to join this list and promise that it is usually a very low traffic mailing list.
The other available mailing list can be found at Mailinglists.
The QGIS project is always looking for people who are willing to invest some more time translating QGIS into a foreign language - even perhaps to coordinate the translation effort.
We are trying to improve our project management process and spread the load more evenly between people who each have a specific area of responsibility, so any contribution you have to make will be greatly appreciated.
If you would like to nominate yourself as a coordinator for a new language please go ahead. If more than one person nominate themselves as coordinator for the same language, please contact each other and resolve how you will manage your efforts.
Please contact the Community Assistant or the GUI translation team leader to see you name entered in the About Box of QGIS.
If you like to help translating QGIS into a your language please assign to the translators mailing list and ask who is already working on that language to coordinate and collaborate.
To start QGIS with the appropriate localization, run qgis with the option –lang=<language code> or change localization in QGIS under Settings -> Options -> Locale.
The QGIS interface is natively programmed in English. However, it is designed to be translated into any language quite easily. At this moment over fifty other languages are already available (though not all well maintained).
All available languages are listed in the QGIS About dialog. It also shows how much of it has been translated yet. The entire interface contains over ten thousand pieces of text and a complete translation will take days if not weeks to be finished. Besides that, the rapid development of the application continuously causes new and edited texts to be translated. A huge effort and your help will be appreciated!
The web-based translating platform Transifex is used for all QGIS translations; the desktop application itself (or GUI), the documentation and the web site. So the first thing you need is an account to login and get started.
Some QGIS organisations are listed now, among them are QGIS Desktop, Website and Documentation.
Now you will need to wait for the maintainers to process your request. You will be notified by email when your request has been accepted.
With requesting a new language please bear in mind that we try to make it as simple as possible. Just ask for the language you want to translate (regardless in which country you reside). Only if there are notable differences in the languages (for example portuguese in Portugal in Brazil) we will create its own version.