Initially $.session.language must return the language that is set by the request header parameter "Accept-Language" as per the doc.
http://help.sap.com/hana/sap_hana_xs_javascript_reference_en/xsruntime.js.html#line973
My client by default sends the value for request header Accept-Language as "en-US". But i don't find the value to be set in the xsjs $.session.language
but instead It just returns an empty string!
-Sakthivel