All installed languages are located in System > Localization > Languages
You can easily add new languages using Language extensions. There are several free Language Extensions available on AbanteCart Marketplace, You can find it just right in your AbanteCart Admin > Extensions > Get Extensions section.
In case you want to add language manually AbanteCart give you choice to translate all language definitions manually or via Google Translate API v2 (paid service)
Create New Language Manually
Take a note when you create new language there are two approach:
Create language as an extension for your new language. Pros - you can share after you are done. Cons - you need translate all definitions in the files only.
Create new language in admin with basic settings. Pros - easy manage translation in Admin > System > Localization > Language Definitions and able to run Automatic Translation (Install google translate extension and translate all your store to any language you want. This will use google paid service and will cost few dollars). Cons - you can not share your work.
Various language settings can be configured in AbanteCart Admin
The default language your store uses. Clear your browser cache to see changes.
This globally enabled translation of missing text definitions or language specific data if text values are missing for used language. Note: Auto-translate will translate newly created content only, if you want to translate content when edit, please set Override if source language text was changed setting to ON.
Override if source language text was changed
If set, text in all languages will be replaced with new translation if source language text is edited. NOTE for Google translate API users: Can cause many translations.
Source language for translation
Select source language to be used for auto-translation. Will work only if you save translatable content in selected source language only. If you change texts in any other languages, translation will not be happening.
Text Translation Method
Select method you want to use for translation. Default method is a straight copy of source language text also others methods can be available if any translation extensions installed. For example: Google translate extension which one use Google Translate API v2 to translate from source language to all other available. See list of supported languages by Google translate API v2.
Load missing language data
Easiest way to fill missed dynamic language data like menu, category names etc
Once new language installed You able to Load missing (not translated) language data from any other language installed in your store. In Admin Front go to System->Localization->Languages and click Edit button opposite new language. Just select Source Language to copy from and click Load button.
This action will copy all missed language data like Product's and Categories names, descriptions, Length & Weight classes, Order statuses, Tax classes ... etc.