If by recent, you mean anything in the last two decades. Deadpool's yellow speech bubbles started in his first solo title. The prior limited mini series like The Circle Chase and sins of the past had white bubbles with a yellow border. I can't recall if any of his appearances prior to Deadpool Vol. 1 Issue 1 had the yellow bubbles, in X-Force at the time.
Unique speech bubbles or thought boxes are shorthand for the audience to tell certain aspects of the characters both in and out of universe. In Deadpool's case, it's that he's very weird in universe. Other characters also have unique bubbles. Cable is often blue. Superman had yellow while batman has blue, green lantern green in some of the pre Flashpoint Justice League comics.
His little yellow boxes, meant to be internal monologue, are also spoken, as Deadpool can't keep his internal thoughts to himself. Oh what fun he has with his little yellow boxes. Due to Deadpool being considered a Crack pot, people just ignore this as crazy babbling.
As of Vol. 3 written by Daniel Way, some bastard white boxes have shown up, supposedly both Deadpool second internal voice or the Arthur, Way, interacting with him. They suck.