The average person reads at a little over four words per second. Although this sounds fast, it can be greatly sped up by simple methods. The reason that people read at this speed is they usually subvocalize the words they are reading in their head. The other reason is that your eyes have to move across the page while reading something normally. The speed reader fixes both of those problems by flashing the words on the screen at an uncontrollable speed, forcing you to read the words too fast to vocalize. It also puts the words in the same place so your eyes can stay in place while reading.