Hi,
I think standard descriptions and objects should be visible with language selection while logging in.
For custom objects you have to maintain object list and piece list.
check below links as well
http://help.sap.com/saphelp_nw73/helpdata/en/4a/5d6828e11315c9e10000000a42189c/content.htm
https://scn.sap.com/thread/2118018
I do not think there is any automatic way. You have to do manual work for all the existing Z objects.
Thanks and regards
Kiran