Because Chibiusa's second "Tasukete!" in the original wasn't a direct response to Luna's "Chibiusa-chan!
You can only assume that it wasn't a direct response. There's nothing to actually prove it was not. Actually you know what as I went back to watch that scene I think I noticed something...Usagi's mouth is also moving when Luna shouts? That seems odd... I went back and check other times when Usagi was running to see if maybe it was meant to simulate her breathing or something. And I can't seem to find an example of her running with her mouth moving when she is not talking. Now I wasn't about to check every episode but the seven I did find in the first two seasons that I knew of all had the mouth not moving. Which has me thinking that maybe originally it was going to be Usagi yelling but then someone realized Usagi calling for Chibiusa and being heard then Sailor Moon showing up instead may have jeopardized Usagi's identity...thus instead Luna became the one shouting. Because it also occurred to me...Chibiusa obviously could not see Luna while she was running for her life. So if you want to say she did not know Luna's voice (I'll get back to that in a moment) then why would it actually matter if she heard her since she would not have any idea it was actually Luna that was yelling her name? So where is the actual damage then if it does not actually reveal Luna's ability to talk to her in that moment? (A fairly moot point I will address later too)
Once the two sisters grab hold of Chibiusa right after Usagi's transformation sequence finishes, the three of them stop running, allowing Sailor Moon to appear before them within a reasonable time span.
Except again Usagi also had stopped running shortly before that. You are also still ignoring my question of why Usagi suddenly decided to transform in the park if she didn't see/hear anything.
Okay, what does any of this really have to do with the primary point of concern being that Chibiusa is not yet supposed to know that Luna can talk and thus should not have had her dialogue written as a direct response to Luna's dialogue?
This was in direct response to this: "This is further supported by the fact that Usagi transformed into Sailor Moon while Chibiusa was running towards her and being chased by Petz and Calaveras, and yet none of the three of them ever acknowledge their having seen Usagi turn into Sailor Moon, and all three act surprised to see Sailor Moon standing before them after Usagi finishes transforming.
" I was disputing the claim that Sailor Moon was in front of them and thus they all would have seen her transform and reacted if she was in earshot.
The fact that Chibiusa didn't notice Luna's dialogue implies that Luna did whisper quietly enough for Chibiusa to not hear her, with the audio quality of her dialogue being loud enough for the viewers to comprehend what she's saying.
Or that again Chibiusa was not startled by Luna talking and was more concerned with the Black Moon droid trying to capture her. Oh and I just realized I had completely forgotten about Chibiusa's debut episode where not once but TWICE Chibiusa was hiding in the room when Usagi was having a conversation with Luna. The first time she was hiding under water in the bath where I guess you can say it may have been hard for her to hear, but then later that night she is just hiding under the covers in Usagi's bed when Usagi and Luna are talking...which yeah there is no way she could have not heard them both. Plus Luna spoke again in the next episode when Chibiusa was using Luna-P to hypnotize Usagi's family. Again no plausible reason why amid total silence and standing only a few feet away Chibiusa would not have heard her.... Really though this whole debate is stupid because not even one scene later in the Sleeping Beauty episode Luna shouts "Sailor Moon, be careful!". This was in the Japanese and both English versions. Guess where Luna was standing seconds before she was shown yelling
Both Luna and Artemis also talk several times after Sailor Moon has been put to sleep. In retrospect Luna really was pretty freaking terrible at keeping her secret...and if you still think Chibiusa did not know Luna could talk before the Sailor Moon reveal I dunno what to say.
One would think, yet the future version of Luna or any of the cats was never shown in the R anime, providing no onsceen evidence within that season that Chibiusa knew the future version of Luna.
Okay sure it wasn't shown in R but we eventually learn that Luna's daughter Diana is Chibiusa's pet/friend... So let's not forget we are talking about the Viz dub here where the people behind it certainly know that fact. So technically pretending Chibiusa does not know about Luna seems more like a retcon based on what we know now...
Do not forget that at this point in the series, Chibiusa's true identity as being Usagi's daughter is not yet known. From a narrative standpoint, we should not yet know that she is privy to such information about Luna being more than just a normal cat. For all intents and purposes, any knowledge of Luna she would have from the future shouldn't yet be made known to either Luna herself or the audience.
Well technically we did see Demande's hologram of Chibiusa's mother at the end of the previous episode who bore a remarkably similar appearance to Usagi where a good portion of the audience should have had a pretty strong idea of whom she might be if they did not already... That is besides the point though as again we are not really spoiling anything for the audience with Luna being heard while running that would not be spoiled about a minute later when Luna speaks again with Chibiusa never reacting to it in surprise... In the heat of battle Luna forgets herself again and never realizes her slip-up and Chibiusa has other things on her mind besides keeping up the charade of being oblivious.
We do get a surprise reaction of Chibiusa learning that Usagi is the legendary Sailor Moon and that Usagi's friends are the other Sailor Senshi, as well as a scene of Chibiusa having to ask Mamoru for confirmation that he is Tuxedo Mask. If she didn't believe Usagi and Sailor Moon to be the same person, then why would she assume that Usagi's cat and Sailor Moon's cat were the same cat? Or that Usagi's cat was the same cat from the future who never even appeared in the season that this all happened in?
I never said anything about Chibiusa knowing Usagi was Sailor Moon because she obviously does not. Nor does she know the identity of the Inner Senshi or Tuxedo Mask. However not knowing that stuff has nothing to do with her knowing or not knowing that Usagi and Mamoru are a past version of her parents. I made a more detailed case on this last August in this thread
, so I'd rather not rehash it and sidetrack the current thread with that theory discussion. If you want to reply and debate there then feel free. (It had however slipped my mind to mention about Chibiusa knowing Luna was her mothers cat and Usagi then having an identical talking cat named Luna as being another piece of strong evidence that she probably always knew...part of me wants go back and edit that in...How did I miss something so obvious.)
To your other point though I will say that until this moment Chibiusa had not really seen Sailor Moon interacting with Luna so would certainly not have thought of her as Sailor Moon's cat. (Closest she came was Luna was in the charm shop when Chibiusa broke out of the place Usagi has stuffed her at the same time that Sailor Moon was still there. But Chibiusa already knew Luna was there with Usagi and she witnessed no interaction between Luna and the senshi that we are privy to.) The Sleeping Beauty episode is the first and only instance she witnesses Luna actually working with Sailor Moon prior to learning Sailor Moon's identity. Plus as far as saying because she does not recognize Sailor Moon as Usagi that she would not recognize Luna as Luna...that is not at all the same thing. We know there is some kind of magical effect that conceals a senshi's identity when they transforms there is no other way to explain "S season" without all the senshi being totally faceblind/brain-damaged. Luna does not transform therefore there is no magic at work that would prevent her from being recognized? A black cat named Luna with a crescent moon mark on her forehead. How dumb do you think Chibiusa is that she would not question that they might be the same?