Since I’m Japanese and speak both languages, I’ll weight in on this one a little with a point some single-language speakers might not experience firsthand.

There’s a kind of artificiality with the anime English dubs that just come from the culture not translating through. That is to say, language inherently has cultural sensibilities built into them. People speak, talk, and act very differently in different countries, and localizations ultimately cannot bridge a gap that fundamentally cannot be bridged. For example, I end up subtly (and not so subtly in certain instances) speaking differently in Japan than in the US because of the differences in culture and speech structure—and I’m still the same person saying the same things! For example, I noticed as a kid that in anime dubs, certain declarative lines (like, I dunno, “It’s time to duel!” from Yu-Gi-Oh! or something) are a little campier and more awkward in English in a way that I don’t feel it being awkward in Japanese. They’re also enunciated in a kind of strange way, in my opinion. I’ll also say, I never feel these kinds of dissonances watching Western animations, like Disney movies, or the Cartoon Network shows I watched as a kid.

I think a good way to demonstrate this in the opposite way is talking about American sitcoms dubbed in Japanese. I haven’t watched them much, but with the little I saw, they sound weird. Everyone’s overacting or acting strange and the word choice is different from what normal people choose, because they’re trying to preserve the vibe and lines of these American sitcom shows—which just are not and cannot be Japanese, especially the style of humor. It’s kind of an extreme example, but these American sitcoms (and yes, they’re kind of stilted in English too, but believe me, the difference between the American sitcom vs American normality and speech is less than the difference between American sitcom dubbed in Japanese vs Japanese normality and speech) gain a certain aesthetic to them because of the dubbing process having to bridge a gap between Japan and the US in a way that’s not really possible because the American sitcom just doesn’t naturally exist in Japan. I’d almost describe it as a sort of cultural uncanny valley.

You see this sort of thing in anime in a more pronounced way when you have characters ending their lines with “-kupo” or whatever. It actually isn’t really all that jarring in Japanese in the way that you’d think it would be. I mean, people don’t talk like that, but jarringness is relative, and when localizing, you’re inevitably going to end up with things that don’t fit in, which, metaphorically, adds artifacting into an otherwise clean(er) image.

Ghost Stories is an outlier here, obviously, but I think what that dub succeeds in more than anything is by making Ghost Stories actually, legitimately Western, because none of those jokes would be written in Japanese, or even thought of. If they took that English Ghost Stories dub and re-dubbed that dub into Japanese, it would be more awkward, and the jokes wouldn’t quite land, especially in Japan, where this new re-dub would be for.

So basically, with “Japanese voice acting in anime isn’t inherently flawless. It’s your unfamiliarity with the language and its natural tones/speech patterns that give you the illusion that it is”—I think the first part is true. Japanese voice acting isn’t inherently flawless. But I don’t think the second part is true. I’m familiar with both languages, and it’s not the unfamiliarity with Japanese that makes you think it’s better, it’s your familiarity with the dubbed language and the fact that you notice that characters feel a little more stilted or talk more strangely than they should given normal speech standards that makes you think the dub sounds worse. Of course, tones and speech patterns affect the way people hear things, but that’s not an illusion. It’s a built-in part of language that has a tangible effect on how we perceive and interpret things, as well as how you write characters and lines, which doesn’t necessarily carry over in the localization process.