That was a bit unclear, I apologize.
_encode() and _decode() are method used when the cache system in roxen byte compile, in my case, RXML-variables. My class need to do the _encode() and _decode() itself since the Calendar object needs to be decoded to a simpler data type, in my example an array, and from the same array encoded back to the Calendar object in _encode(). So to _decode() the Calendar object I need to know the language in that so I can recreate the Calendar object, to whatever language is set in it, correctly.