Foremost, it is our crowning intellectual achievement as a species. I made that point in Through the Looking Glass. "Never again in our lifetimes will we achieve anything as complex and profound as our ability to share what is essentially an infinity of shades of meaning. Furthermore we are able to do this in a novel fashion each time – even if we wish to express exactly the same message."
What I have been thinking about lately, though, is the dynamism of a given language. English, in particular, is in constant change. New words emerge, and a few disappear - so the lexicon is always changing although the rules stay pretty much the same.
To quote myself again, "Language is also a gift most of us develop with minimal effort. No one teaches us that plurals can be created by adding an 's.' No one teaches us that adding '-ed' to verbs will usually result in the past tense. We simply abstract those rules of grammar by listening to those around us. Young children often say 'foots' or 'goed' instead of 'feet or 'went.' They didn’t hear those words; they just figured it out. That’s remarkable! Of course, they have to learn later that there are exceptions to many of the rules." They regularize but too often.
That regularization of verbs also occurs as part of our language's evolution. Some verbs that were once irregular become regularized. Holp has become helped. Swole has become swelled. Chode has become chidded. What's intriguing is that this happens mostly to words that are used less frequently.
High frequency verbs tend to stay irregular. I assume because you hear the irregular usage a lot. Choose, chose - not choosed. Do, did - not doed. Catch, caught, - not catched. Is, was, - not beed. Those are the kinds of errors children often make as the apply that -ed rule.
Then there are the words that are currently in transition where your hear both forms used. You're likely to hear both burnt and burned, dreamt and dreamed, proven and proved, shown and showed, leapt and leaped. I imagine, however, that in a few decades the transition will be complete, and you will only hear the regularized version.
It perplexes me that American English has more regularization the British English. For example, we're more likely to say burned; they're more likely to say burnt. Why? Was it Churchill who said of us that we were two countries divided by a common language. Indeed.