... nope, I don't see how that can be achieved short of shifting "understandable" around between the characters' primary (voice) and some secondary (e.g., subtitles) medium. It needs to telegraph that it's not the character who has suddenly changed, but some technicality of the movie presentation, so subtitles seem to be a good choice / established convention. Unless we can think of (and then establish) some new, superior "code" ... ?
I think having the characters switch from PLAIN to their native language shouldn't be too awkward if the audience has enough context to understand that they are in fact never speaking in PLAIN. First character interactions should be in their own language, and then they'd all switch to PLAIN when necessary.
For example, if character A speaks and character B replies, then character B understood character A. If character A speaks and character B looks confused, then character B and character A do not undertand each other.
I remember they did something like that in Vikings, where the character's voices sometimes switch to Old Norse when the filmmakers want to make a point that the characters cannot be understood, or in an emotional, historically relevant moment (if we had to translate that to our SSSS show or movie, I think for example that all of Lalli's and Onni's runos should be in Finnish, and maybe without subtitles, just like in the comic). Also I'm all for the characters having accents when speaking English, it'll work as a reminder that they are from different countries.
Something off the top of my mind would be to use movie theaters' current-day multi-channel audio equipment: Have the character's "real" voice (original language) come from the direction of his face on the screen, and simultaneously have an omnidirectional "whisper" in PLAIN. Most spectators should be able to focus on only one voice/direction, as that's an ability we routinely use when we're chatting with our company in a full restaurant or the like. But of course that probably ruins the chances to have the same movie broadcast within the century, as both TV sets sold and signal encoding standards haven't fully adopted even stereo thus far ...
Mhh... I'm not sure about that idea, it would make the whole thing sound like a badly dubbed interview from a documentary. I know I wouldn't want to watch a movie dubbed like that. ^^"
I’m not against subtitles when it comes to movies in foreign languages (I need them to understand what’s happening after all), I’ll take that over dubs any time of the week, but I do feel like they take away from the immersion, unlike when watching a movie without subtitles on in which you understand what’s happening and being said.
What I suggested would be like subtitles in a way, still needing to be read, but now they would be part of the animation itself, instead of being something superimposed post-production. They’d be part of the world, like how the speech bubbles in the comic itself are.
And trust me, I hate dubs as much as anyone else. I don’t like it how the lip movements don’t line up with what’s being said.
With all this said, I can still see the benefit of having everyone properly speak, even with subtitles on, both from a “learning a new language” standpoint and a “seeing the characters you know and love actually speak” standpoint.
But, in the end, it’d be the animators’ decision on what way they want to go, since lip-syncing is pretty hard stuff if you ask me.
We absolutely could find a way to make the subtitles seem less intrusive! By changing the typo for example, or animating them in a certain way that would fit the scene. We'd also need to add flags or another type of code that informs the viewer of what language is being spoken. I think the average, non-nordic viewer can't always tell the difference between Norwegian, Icelandic, Swedish, Danish and Finnish, so we'd have to take that into account.
Well, concerning lip-sync, the animators would have to animate the characters' mouths moving anyway, so might as well make it stick with the audio.