We hope to make this more streamlined in the future. For now, to translate Elefant into a new language and submit it for inclusion in the project, here are the steps:
Install a copy of Elefant from the latest master branch on Github. You can do this through Git, or by clicking the Zip button on the page.
Once you have Elefant installed, go to Tools > Languages. It will first build an index of all the text in the default install, then present you with a list of languages. Click Add language to add a new one.
Enter the language name, code, etc. See here for a list of language codes. We recommend entering the language name in its own language, for example Français instead of French or Español instead of Spanish.
Once the language has been added, click Edit to edit its translations. There are approximately 1434 words in total.
Once you've finished translating, post the translation file, found in the lang folder of your installation, to one of these sites and link to it in the Elefant forum under the I18n category.