#faroffwebcomic

It's really neat that you ask how I think the story would go if their countries had different languages, because I do actually have headcanons about Fenn and Tobias' knowledge of other languages, despite having never thought about this scenario exactly before. Basically, I think Tobias would've been taught multiple different languages in his studies, but in Sona I think learning multiple languages would be looked down upon or maybe even banned (it helps the government keep them brainwashed if their ability to read, understand, and learn from other countries is limited), so I don't think Fenn would've been taught another language aside from his main one.

SO! If their countries had different main languages. I think there would be a huge language barrier on Sona's side, because I think the majority of Sonan soldiers wouldn't speak the Vaylinian language, including Fenn (I can see Oskar knowing it and having taught him some words and phrases, though.) However, I think it's very possible and maybe even likely that Tobias would've known the Sonan language.

Therefore, in the beginning they would've spoken entirely in the Sonan language. We probably would've only seen the Vaylinian language being spoken when Tobias is alone, in flashbacks, and when he's saying something he doesn't want Fenn to understand.

I also think Fenn would have a huge mental rule against speaking the Vaylinian language at all, to the point where he'd see it as a betrayal to his country, so there would've been no teaching him anything in the beginning unfortunately. He probably would've gotten very aggressive when hearing Tobias speak in the Vaylinian language as well, because I think he would take it as 'I can't understand what he's saying' = 'he's planning something', which, as we all know, means he'd go absolutely berserk and DEMAND to know what he's saying. (It would be really funny if Tobias just came up with random bullshit and told Fenn that's what he said LMAOOOO)

But over time, as he got closer to Tobias, it would've changed a bit. Especially after their truce agreement, I think he'd still ask what Tobias is saying when he speaks in Vaylinian, but it would be more out of genuine curiosity rather than paranoia. Still no speaking it himself, though. Maybe he would've spoken it to Tobias for the first time around the same time that he let him stay in his quarters, and started trying to actually learn it shortly after the current point we are at in the story? (For any time travellers, the "current point" as of this post is Episode 83 - Truth: Part 2)