Also, if you watch the Borg Queen in Voyager, she's about as detached from the collective as a potted plant.
Borg Collective: Vessel identified. USS Voyager. We will pursue and assimilate.
Borg Queen: No. They have not compromised our security. Let them go for now. I'll keep an eye on them.
I can't really defend sloppy writing... any more than I can defend Data's cat changing breed and sex, Spock using the term "ancestor" to apparently describe his mother, Kirk saying that he had a brother once and got him back (referring to Spock) and apparently forgetting about his brother Sam or Khan recognizing Chekov (actually, I can defend that one).
This is writing done just for our (the audience’s) benefit. It’s to let us know that the Borg have identified and located an intrusion and that the Queen has something up her sleeve. Why the Queen and collective need to talk at all is beyond me. According to the Queen in First Contact, linguistic code was primitive. She never spoke to a drone or to the collective. -Neither did Locutus for that matter.
It’s kind of like why Klingons seem to speak English, even when they are not around other Earthers. Heck, even when Starfleet officers go undercover, it seems that those they are infiltrating alter their language so that our heroes can understand it. Or why villains have to monologue their magnificent plan to either the hero, or their minions (who should already be aware of the plans), all really for the audience’s benefit.
The only defense I can give is similar to something Troi said in the TNG episode, Time Squared. In it she discusses the duality of our own thoughts when making a decision. When we’re pondering a decision in our heads, who are we talking to? -Just ourselves, of course. This still doesn’t answer the question as to why they actually needed to speak… but, like I said, it’s sloppy writing.
The Borg race evolved behind the scenes over time. Initially, they were supposed to be the bug creatures from Conspiracy. They were then changed to a race of cybernetic beings with a collective consciousness that were only interested in technology. They weren’t interested in biological life forms. Then came The Best of Both Worlds where they wanted to assimilate the human race. Even though they were conceived of as a collective mind, it would appear that Picard is assimilated, given a name and then leads the attack on Wolf 359. After the Hugh fiasco that makes us believe that they are no longer a collective mind at all and makes them just lame villains (but we now established that the Borg have transwarp capability) they come back for First Contact. This time showing that only a handful of ships were effected by Hugh’s individuality… either because it was never intended to effect all of the Borg, or the writers realized it was a stupid idea and a waste of a good villain. So a queen was created to establish drama and give us a focal villain. However, her answers as to her role within the collective are cryptic as is her answer as to why, if she was on the first cube that was destroyed over Earth, she’s still alive.