From ABobrik87 of Youtube:
"It's from Henry V, and it is the St. Crispin's Day speech, said by Henry right before the battle between the English and French is about to begin. In the original text, it finishes with "Upon St. Crispin's Day" instead of "Upon this day"; I assume they didn't think anyone would recognize the original text."
He goes on to say:
"I am so sad that they used the beautiful St. Crispin's Day speech for these ridiculous games. Because, honestly, how often is the average PS3 gamer going to recognize Henry V and appreciate its greatness?"
I haven't gotten that far in History yet I guess.