[Don't know how to address people in trac (#4911) correctly, so asking here before implement feature so patch is missing.]
For changing language in lobby or in gamesetup or in-game it can be good to have language changing possibility within the options window f.e. if want to change from native language like german to english, when ingame or in gamesetup, for looking up proper english name for a map or unit to talk to others in english, but then switch back to native language (german), this can be really helpful. Interest?