I may be old, but some of these are just plain wrong. Lead for led? From Ben Yagoda, writing in The Week.
The psychologist Steven Pinker was once quoted as saying that the best way to tell if someone was under 30 was if they were comfortable using "fun" as an adjective.
About 15 years later, that still seems on target. The farther away in the rear-view mirror 45 is for you, the odder it seems to hear something like "his party was funner than hers." And the younger you are, the more it seems perfectly normal.
In my new e-book, You Need to Read This: The Death of the Imperative Mode, the Rise of American Glottal Stop, the Bizarre Popularity of "Amongst," and Other Cuckoo Things That Have Happened to the English Language, I write about fun-as-adjective and a number of other trends that young people have brought into the language.
Note that I call these "trends," as opposed to "horrible crimes against English." I know that some people decry new word-meanings and usages, while others defend them. My purpose here isn't to engage in that argument but rather to chart the course of change.
To that end, I thought it would be fun to come up with a Pinker-like watershed age for some of these developments. Instead of just guessing, I devised a survey and sent it out via social media. First, I asked people to put themselves into an age range (18-25, 26-35, 36-45, etc.), and then, for each point of usage, I asked whether they themselves spoke and wrote that way.
Now of course, given the number of English speakers in the U.S., not to mention the world, the results aren't scientific. And some people probably reported being more "proper" than they actually are. Finally, there are clearly factors other than age at work here, most obviously education. But the results are still pretty instructive.