In ExpressionEngine, all language packs can be found within directory “/system/expressionengine/language/” (default English). Sometime there may need to get list of all these languages at front end. There doesn’t seem any template tag for it but it can be easily achieved with a couple of line of code and a small plugin can be developed for the same.

Where $languages is the array of all the languages.

More about language packs is documented here.