It is a fact that some people have the opinion that there are hard rules to language. Better?
More seriously, I think we're in violent agreement, the difficulty is how we parse the word "rule".
If rule means "something that must be done or you'll be a bad person and the world will end" as many language prescriptivists like to use, then it is a fact that languages do not posses rules of this sort.
If rule means "a mutual set of understood guidelines" then yes, I'm in full agreement that languages can have sets of customary rules that aid construction and understanding, but this set of guidelines is incredibly fluid and can change as you've described including temporal, generational, socioeconomic, ethnic, fluency and other sources of variation that can alter the set so profoundly that two speakers of the same language can be more or less unintelligible to each other yet still be said to be speaking the same language!
Back on topic: "a green great dragon" sounds awkward unless we're having a discussion about the colors of "great dragons" in which case it's perfectly ordered and "a great green dragon" makes no sense since we're not talking about sizes of "green dragons".
More seriously, I think we're in violent agreement, the difficulty is how we parse the word "rule".
If rule means "something that must be done or you'll be a bad person and the world will end" as many language prescriptivists like to use, then it is a fact that languages do not posses rules of this sort.
If rule means "a mutual set of understood guidelines" then yes, I'm in full agreement that languages can have sets of customary rules that aid construction and understanding, but this set of guidelines is incredibly fluid and can change as you've described including temporal, generational, socioeconomic, ethnic, fluency and other sources of variation that can alter the set so profoundly that two speakers of the same language can be more or less unintelligible to each other yet still be said to be speaking the same language!
Back on topic: "a green great dragon" sounds awkward unless we're having a discussion about the colors of "great dragons" in which case it's perfectly ordered and "a great green dragon" makes no sense since we're not talking about sizes of "green dragons".