AMX Mod 0.9.9 comes with two languages: English and French. If you feel like you could become a translator, just let us know ;-).
A. File format
Translations data files are located in the addons\amx\lang folder. They are specific to each plugin (this way there can be no conflict). Here is what they look like:
Thanks to this example you can guess several things:
B. Adding Languages
Well, basically you just have to add your code:"Translation" lines to the translations files.
But if you plan to give your language support to other people, it might be a good idea to create your own .txt file, in which you'll keep only the English strings and then add your translations. Then other users can include (with the '+') your file instead of overwriting the default one. Moreover, it will let them include several additional languages.
It might be better with an example: let's see the following file.
tailor.txt:You want to add German. You could just do:
tailor.txt:But adding this to the default file is not recommended: what would happen if somebody else provided people with his own Spanish translations added to the default file? Users who'd want to add both German and Spanish support would have to merge the two files.
Instead of this, you would better create your own translations file:
tailor_de.txt:Then people who want to use your translations will just have to add one line to their default file:
tailor.txt: