Some language stuff has been mentioned on the dash, so I believe I'll follow suit on some specific headcanons myself!
Regardless of fandom, Felix's primary two languages in tandem are New Mexican English and animal/creature speak;
Pokemon for that verse, and Animalese for the villager verse.
Pokemon is very specific how this language is intended to work- with the mons having an innate ability to get what you Mean from "the heart" and always mentions shit like having a 'pure heart'- all the canon protagonists have this. But, it's not exact language and likely relies on nonverbal tonal elements such as inflection, context, and volume.
This is probably, in my opinion, from having shared elements with human languages in the way that cat facial expressions are reliably identical enough to human expressions, compared to other animals such as dogs. Heck, even meows seem to have dialect- echoing their country of origin in a way.
Felix does fine generally speaking, but it can cost spoons to stretch outside those two; translating verbage is fine, but things such as tone, pronunciation, and volume outside of his own is mentally irritating. Sounding close to say, a midwestern/dictionary or new york accent requires opening the mouth and forcing vowels and dipthongs, pauses ("commas" in writing), etc.
There's also just a bit of strain that comes from a maturing voice on HRT- the new adam's apple and thickened vocal cords operating on obsolete muscle memory.
Felix is not what I'd consider 'fluent' in Spanish or Japanese; but a kindergarten level with an understanding of latin roots goes a long way.
these were both locked in before age 13, so are the most likely candidates of a third/fourth language.
Pikachu as a species are canonically liable to pantomime or draw- they're not stupid, and know full well how to handle language barriers and will do so to be aggressively pack animals-
pretty much all they wanna do is cooperate to human levels with every pokemon that they meet. (which is why they're a pokemon in particular that I consider way more anthromorphic to dismiss as a 'pet'), and Vanillabean follows suit.
They're both examples of active good listeners, however- and will definitely, most certainly get irritated/taxed by those who are not so good, and unreasonably so.
Language is one thing, with consideration being another entirely; patience, and etc.
It's both skilled and willful.
Volo here (and by extention, Cynthia) have a first language of Greek, with a secondary of Kantonian- Volo actively self-harms mentally by forcing the latter with a bubblier tone/inflection; he should sound much softer.
His relationship with a third language depends on the protagonist; I headcanon that he understands them much better than the average hisuan, with the exact pronunciation dependent; the closer they are, the more likely he'll pick up a dialect accent that they have than a textbook inflection.
My Cogita has a voiceclaim that speaks Paldean/Spanish, so it's highly likely that's her native with the Celestic Language/Greek being tandem/secondary; the most important part is the quick cadence and flair- Could be coincidentally like Felix's case where instead she simply speaks the languages "*in Spanish*"; accents occasionally transcend past their original language (often how dialects form).
Cynthia likely is also like this, but with a positive spin; she's not quite so pessimistic and hurt, but it can come off as a blonde moment when she flubs it.
