One grammatical issue that kinda bugs me is when people state that action B is “[x] times [more/less of something] than” action A. For example, a person might say that Vehicle B is moving “three times faster” than Vehicle A. What the speaker actually means is that the second vehicle is moving at three times the speed of the first vehicle. For example, one horsedrawn carriage might be traveling at five miles per hour while a bicycle might be traveling at three times that speed, meaning 15 miles per hour. Thus, the communicator should have used the phraseology “three times as fast.” But unfortunately, the speaker clearly took no effort to articulate his message accurately, so he wound up implying that the bicycle was actually going four times the speed of the slower vehicle (i.e., twenty miles per hour).
If you play your music “one time louder” than I play my music, that obviously does not mean you are playing the music at the same volume. Rather, if you are playing “one time louder” than me, that must mean you are actually be playing twice as loudly. Hence, “two times louder” would mean three times as loudly, and “three times louder” would mean four times as loudly. The same goes for vehicular speed, and the same principle applies for any comparative adverb or adjective.
And don’t even get me started about phrases like “three times slower.” What in the world could that possibly mean? If an object was moving one time (100%) slower, that would presumably mean that the object was not moving slowly, but was in fact stopped altogether! So if something is three times slower, is the object moving at negative speed? (And unless you are referring to vectors, which describe direction, then negative speed is obviously impossible.) If a guest lecturer speaks “two times slower” than your professor normally talks, doesn’t that mean that he is speaking at a negative rate and that his lecture never ends??
Anyway, the instance that recently brought this matter to my attention was the claim that Justin Bieber’s songs sound better when they are “slowed down 800%.” I don’t think the communicator actually means that we should play Bieber’s songs backwards, so I imagine the song is actually slowed down 89% — down to one ninth its normal speed. But who knows exactly what the person means. He is in fact correct about one thing, though: Justin Bieber does sound better this way.