Another one of Bogle's self serving comments. He's a legend but rarely unbiased. The key difference is the speculator buys it purely in the hope of flipping it. The investor considers the fundamentals of the investment. Time horizon is irrelevant. You can have special sits which you are in and out of in a month or so; but it's definitely an investment.
We are all hoping to flip our investments in the equities market; no one is holding forever. Unless you intend to die and pass your ownership interest to heirs.
Buffett's favorite holding period is forever. Cuban points out that non-dividend stocks aren't much more than baseball cards. Kiyosaki argues that the reason people suffer financially is that they purchase liabilities and list them under the asset column.
The difference between investing and speculating is whether you get paid for owning it or only for finding a greater fool to relieve you of it. The wheels have come off the equities market because management has realized putting on a convincing show for speculators nets more dumb money than actually succeeding as a business worth owning.