Stop talking to yourself when you read. People talk to themselves in 2 ways, by:
vocalizing, which is the actual moving of your lips as you read, and
subvocalizing, which is talking to yourself in your head as you silently read.
Both of these will slow you down to the point in which you find that you can't read any faster than you can speak. Speech is a relatively slow activity; for most, the average speed is about 250 WPM (words per minute).