The vowel sound in rag is modified when the silent e is placed
at the end to form rage. In both of these words, the g sound is
heard as the "j" sound also because of the silent e at the end of
the word. In order to maintain the integrity of the phoneme and
clarify what sounds are expected by our crazy English language, the
e must be maintained in all forms, otherwise the "rage" sound in
"courage" or "courageous" becomes a "rag" sound with the long g and
short a.
We would not wish to refer to someone as cor-rag-us, now would
we?