I'll write more about this episode later, but what was the episode where Obrien know how to speak Trill? I don't remember that at all.
Also, just curious how do you and Chris prepare for the show? I remember listening to a Trek Podcast where the hosts were making mistakes about what an episode was or when something happened. I know it's hard to remember everything about all series (Hell, because it's my least watched series, I couldn't tell you what 2/3rds of Star Trek were about) but when it comes to DS9, you guys come across as geniuses. I know you guys are dedicated to the series and that's awesome, but you guys can't remember everything that's happened in the series with each specific character without having doing some prep work. If you do, I'm more impressed. The detail you guys put into the show really is stunning.
In "Prodigal Daughter" O'Brien is reading Trill with Ezri at her family home, so he can at least read it.
So for prep, we research a lot, so it does take time. Places like Memory Alpha, DS9 Companion and ST.com are invaluable. We have both watched the entire series a few times, but there is still more I've forgotten than remember!