I'm going to challenge this idea by pointing to exactly what we are doing in this forum.

Ah, yes, well, I suppose. The vast differences you speak (or type) of are lexical in nature. Most of them are not in the sense of absolutely new words, but rather of new meanings for words. Extensions as it were. In a word, metaphor. The fact that one can read Tom Jones or Tristam Shandy without too much trouble, except an occasionally trip to the dictionary (I am speaking of the grammar of the the language thereto) puts the lie to your assertion. But, heck, what do i know. Maybe you're right.

Ceci n'est pas un seing.