How to create a new language in rosetta : ortograf alternativ

To create a new language in Launchpad, we usually need an ISO code for that language (eg. "fr" for French or "de" for German). If it's a variant of pre-existing language, then we can use the same "modifier" that is used as in the GNU libc locale (example "be@latin" which is a Belarusian variant in Latin script: "be" is ISO 639 code for Belarusian, and @latin part is taken from GNU libc locale for Belarusian in Latin which is named "be_BY@latin").

If there is no ISO 639 two-letter ("alpha-2") code for your language, we can also use three-letter code, and if it doesn't exist, you can ask for one on the ISO committee pages: http://www.loc.gov/standards/iso639-2/ (where you can also check if there is an existing code).

We also need to have plural form information (which is basically a number of variants noun-like words can have when used along with a number, and a formula to determine which variant to use in which case; examples are when we have 1 plural form, i.e. "0 foo", "1 foo", "2 foo"..., when we have 2 plural forms like in English—"0 foos", "1 foo", "2 foos"..., or more, which is common in Slavic languages).

Once language is added to our database, you can start translating right away.

If you want to translate Ubuntu, there is an additional step involved, and that's registering a team named "ubuntu-l10n-LL" where "LL" is your language code, and then we can restrict access to translating to that language to that team exclusively.

Thanks Danilo for your answer,

Do you mean we have to create an iso code first ? That's a bad new :(
The goal is to provide Ubuntu into a writing variation of the French language.
You could check this writing form at : http://www.ortograf.net/

Anyway it's a French derivative, something like fr_alt or fr_oa
Is it possible ?

Thanks Данило Шеган, that solved my question.

This is a FAQ:
FAQ #23: “How do I create a new language for translation?”.