Whilst probably not happening for a while - one thing that did float into my head during a lucid moment was when Paradox Pokémon are introduced, what are their cries going to sound like?
For the "Past" ones, their given names are not actually their names. So like a Great Tusk isn't going to run around grunting "Great Tusk" - and although there are a lot of Pokémon like Gyarados and Salamence who just let out roars, it doesn't seem to fit the aesthetic of the Pokémon like Scream Tail and Flutter Mane.
The whole point of the Paradox Pokémon is that they are regular Pokémon plucked from different timelines but there's no actual relation to their "counterparts" so that's gonna be interesting to see how they go about it. They could end up building on their lore and discovering their origins perhaps?
I hope the Iron guys just regi-grunt kinda that would be funny
In both cases the key thing is their Paradox two-word names aren't their actual names: they're tentative codenames given by scientists to what are essentially a group of unidentified and unknown Pokemon. After all, Koraidon and Miraidon were originally code-named as Winged King and Iron Serpent, respectively, until they gained their true names as Koraidon and Miraidon.
That said, there are two possibilities. Either they will have nondistinctive roars or robotic cries, or they will say their "present-day" counterpart's name.
Now why do I suggest the latter as a possibility? Because the paradox Pokemon's cries in the games are similar to their derivative Pokemon's cries barring a special effect added depending on if it's an ancient paradox or future paradox.
But more importantly, the games have several implications via text boxes that Pokemon in the games do in fact say their names, and we have an example with the Titan Great Tusk and Iron Treads where we get text boxes when they roar just before you battle them.
And believe it or not, here are what their cries in the games are implied to be:
Titan Great Tusk: "Dooon! Faaahnd!"
Titan Iron Treads: "Whirrr! Don-fah!"
As you can see, despite neither of them being actually Donphan supposedly, their cries in-universe have them saying "Donphan" in some form or another. Iron Treads' based on the text seems to be a machine whirring followed by it saying "Donphan" in the way you would hear it in the anime.
So in that sense the other paradoxes would likely follow suit. Brute Bonnet would say "Amoonguss" or some variant of it, Iron Hands would say "Hariyama" with a machine whirr added to it, and whatnot.
The exceptions would be Iron Thorns, Roaring Moon, and Iron Valiant, who would definitely have non-distinct roars or robotic beeps of sorts. Thorns and Roaring Moon are based on Tyranitar and Salamence both of who possess non-distinct roars in the anime, while Iron Valiant is a weird hybrid of Gardevoir and Gallade which would be an interesting beast to make a cry for.
In addition while we need DLC to expand on it the implied lore seems to be a little more complicated with the Paradoxes. Despite Sada and Turo believing they are from the past/future, their actual origins are dubious and logically their existence at all doesn't make sense (hence why they're called paradox), and yet somehow they do exist. In other words, they
shouldn't logically exist in the first place, and yet somehow they do. It's likely related to Terastal energy somehow, which is why most of them resemble current day Pokemon with the same cries very similar appearances, but have different types and stats, and seeing as how Terastal and Terapagos are tied to the types, that may play more into it somehow.
We are definitely going to get a lot of lore on that however seeing as how Liko's pendant is implied to be related to Terapagos and is a major plot point for her story.
