A new way of handling macros that are temporarily redefined
was developed by Bernd Raichle and included in the core of the babel system. Two new macros, for use in the language-specific files have
been introduced.
These macros, \babel@savevariable 〈:〉!:}register and
\babel@save 〈:〉!:}macro, append code to \originalTeX.
This code restores the value (or meaning) of what was saved when
\originalTeX was executed.