I was in San Fran this weekend talking to a friend who said that he was both loquacious and eloquent. It struck me as weird. Maybe because of the alliteration and reuse of the Latin base for voice. But it was more.
On the plane I realized it. Someone who is loquacious may think they are eloquent. Hopefully so, if only to justify their yapping. But it is doubtful it seems to me that an eloquent person would call themselves loquacious.
Hence, if you say you are eloquent and loquacious, the reality is you probably just talk a lot.