Hi Bob,
I'm not sure what source code you are referring to in coming to this conclusion but I believe you are incorrect. On my local machine running windows if I vist the /Secure/ChangePassword.aspx page and I change my browser preferred language to Russian and refresh the page I see Russian characters for the labels and buttons and I recall that I did take localization into account when implementing it.
I do remember a bug like this on mono at one time so if you are seeing this on linux that is most likey a regression in mono, probably in their implementation of <asp:ChangePassword control.
Joe