ISO 639-1 is the standard just about everywhere. To use your API and serve the correct language for the user requires a bunch of tedious code to translate from the standard to your different codes. Please consider changing this.
http://www.w3schools.com/tags/ref_lan...
http://en.wikipedia.org/wiki/ISO_639-1
http://www.w3schools.com/tags/ref_lan...
http://en.wikipedia.org/wiki/ISO_639-1