Inheritance of language environments could be a useful idea,
but I am not sure how much it would save.  Consider this one:

    (set-language-info-alist
     "French" '((tutorial . "TUTORIAL.fr")
		(charset ascii latin-iso8859-1)
		(coding-system iso-latin-1 iso-latin-9)
		(coding-priority iso-latin-1)
		(nonascii-translation . latin-iso8859-1)
		(unibyte-syntax . "latin-1")
		(unibyte-display . iso-latin-1)
		(input-method . "latin-1-prefix")
		(sample-text . "French (Français)	Bonjour, Salut")
		(documentation . "\
    This language environment is almost the same as Latin-1,
    but it selects the French tutorial and input method."))
     '("European"))

We could make it shorter using inheritance, but it is already pretty
short; is it really worth while making it any shorter?