What is proper English? Who decides what's right and what's wrong?
They say that English broke away from other languages around 500AD and for CENTURIES, no one cared about "proper English". It wasn't until around the 1650s that people started paying attention to the English language. It's important to note that this movement - what I like to call the 'Grammatical Revolution' - was riding on the tail of another important revolution: The Scientific Revolution. While the scientists were systematizing our universe, it's not surprising that the writers and academics turned their attention to the English language.
We were already behind. The French had established their Academie decades earlier, and we wouldn't even have a recognized dictionary until the 1700s. But finally, by the 1700s, we had started to define our language, and "proper English" was born.
Thank goodness for that! What would the grammarians, English teachers and language purists have done for the past 300 years if they didn't have these rules and regulations? How would they spend their time if they couldn't be cutting people down for poor language use?
But the fact of the matter is, English is changing. And as hard as people try to fight that trend and focus on their grammar rules and style guides, the language continues to change. This will never end, and it will keep changing depending on how we choose to use the language.