Muhammad Ali has been in decline for decades now, however there was a point in his life when he was probably the most articulate and intellectual athlete who ever lived.
George Chuvalo is a great pick. I've mentioned him and LaMotta in similar threads as this before. I have an interview with LaMotta on DVD somewhere from about 5 years ago and he spoke very well considering his age and the amount of punishment he's taken throughout his career. Ward and Wlad take less punishment due to the amount of holding they do, although Wlad has had a much longer career than him and over twice the amount of fights he has. Wlad is fluent in like four languages, whereas Ward is only fluent in two - English and bullsh*t. However, Eubank took tons of hard punches during his career. The amount of flush bombs he took in his last 2 fights against savage punching CW Carl Thompson alone should have him sounding like an English version of James Toney by now.
Many old time fighters like Carmen Basilio are much more erudite than the fighters today. On youtube I found an interview of him discussing his upcoming fight with Sugar Ray Robinson. He is not only well spoken, but speaks from a time in which it was incomprehensible that the best fighters would avoid challenging themselves against the best. Also in the classic forum a few months ago, somebody posted memoirs of Jack Johnson. The difference in intelligence between the well spoken Johnson and a barely literate buffoon like deontay Wilder is quite shocking.
You guys are mentioning mostly ex boxers who are doing TV announcing...of course they speak well; they wouldn't have their jobs otherwise. Look at the late Carmen Basilio and recently departed Gene Fullmer. Both men were old school warriors who took major beatings, even in winning bouts. Fought WAAAY more than modern boxers. Both were articulate into their 80's, or at least spoke pretty well. That's amazing. Considering the blows to the head given to him by Arthur Abraham, Andre Dirrell is still speaking OK. Let's wait another 10 years to see if guys like Malgniaggi are still articulate.
They have Doctorates in sports science right? Barrera is a qualified lawyer. Just a much more impressive field.
Nicky Piper, MENSA member, speaks very well. Barry McGuigan was another candidate but recently he's becoming harder to listen to. David Price speaks pretty well too.