I will gladly take on wikipedia. I did so recently (and I think successfully) on the topic of the age of the Peanuts characters. I think your citation is using a meaning that comes more from scholarly rhetoric than actual Latin, but maybe I'm wrong.
Yesno, I think I'm right about this not because I looked it up but because I have studied Latin. "Dixi" just doesn't feel right in this case. Loquar has more of a connotation of holding forth or public speaking than dicere. I freely admit to being a jerk for still arguing this, and I also confess I probably wrong (as I usually am), and it certainly sounds better in English in this phrase. However, I am who I am, and one of the things I am is an obnoxious pedant who will argue thing like this until you walk away or punch me. Often even after I am already persuaded I'm wrong.