question about language preference option auto_begin/end

[Uwe Stöhr]

Can anybody explain me what does the option "auto end" do that is in the preferences dialog under 
Language settings? The only code reference I found is this:

if (!lyxrc.language_auto_end &&
            !params().language->babel().empty()) {
                os << from_utf8(subst(lyxrc.language_command_end,
                                           "$$lang",
                                           params().language->babel()))
                   << '\n';
                texrow().newline();
        }
But what is the difference to the case when auto_end is activated?

thanks and regards
Uwe