<?php exec('espeak \'You are visiting my website.\''); ?>
It is pretty straightforward, using the PHP exec(); command to execute the "espeak" command in the Linux terminal. One good note is that "espeak" and "exec();" only like single quotes, so you must use the escape character ("\") before espeak's single quotes to prevent "exec();" from thinking you have ended your command. For example, without the escape, PHP would think that the command was "espeak ". After doing all that, I had a really cool webpage that spoke with real audible words through my Raspberry Pi whenever it was loaded!