The average high school vocabulary is 10,000 words.
The average college graduate vocabulary is 30,000 words.
The English language has about 1,000,000 words.
The good news is that one needs to learn only about 3,000 words to become conversant in English.
4 years in college isn't enough to triple your vocabulary. And the average fluent speaker uses far more than 10000 words. In my second language, I'm slightly over 10,000 words (I keep track of everything I encounter in Anki) and I'm still nowhere near as fluent as a typical high schooler. I encounter several new words daily.
Newspaper vocabulary is dumbed down, and TV even more so, because that's their market.
I'd say it's debatable, but in the right ball park.
English is probably the language with most words, though I've seen estimates around 300k, though even that might be high depending on the definition.
Here's Steve Pinker on it (from his 1994 book “The Language Instinct: How the Mind Creates Language”):
> The most sophisticated estimate comes from the psychologists William Nagy and Richard Anderson. They began with a list of 227,553 different words. Of these, 45,453 were simple roots and stems. Of the remaining 182,100 derivatives and compounds, they estimated that all but 42,080 could be understood in context by someone who knew their components. Thus there were a total of 44,453 + 42,080 = 88,533 listeme words. By sampling from this list and testing the sample, Nagy and Anderson estimated that an average American high school graduate knows 45,000 words—three times as many as Shakespeare managed to use! Actually, this is an underestimate, because proper names, numbers, foreign words, acronyms, and many common undecomposable compounds were excluded. There is no need to follow the rules of Scrabble in estimating vocabulary size; these forms are all listemes, and a person should be given credit for them. If they had been included, the average high school graduate would probably be credited with something like 60,000 words (a tetrabard?), and superior students, because they read more, would probably merit a figure twice as high, an octobard.
> Is 60,000 words a lot or a little? It helps to think of how quickly they must have been learned. Word learning generally begins around the age of twelve months. Therefore, high school graduates, who have been at it for about seventeen years, must have been learning an average of ten new words a day continuously since their first birthdays, or about a new word every ninety waking minutes. Using similar techniques, we can estimate that an average six-year-old commands about 13,000 words (notwithstanding those dull, dull Dick and Jane reading primers, which were based on ridiculously lowball estimates).
http://www.balancedreading.com/vocabulary.html
Specific counts vary widely, as it is hard to measure such things, and what counts as a word is also slippery. But the trend is pretty clear.
-ss