All the gods we meet in Persephone except the titular character are ancient beings who have been around ever since the dawn of time. So I’ve had some readers ask why they speak with a modern dialect.
There’s two reasons for that:
First, linguistically, it wouldn’t make sense for their speech patterns to get stuck in the past. Language is dynamic and ever changing. Not just on a global level, but on a personal one. If you hear a certain word every day for months on end, chances are it will assimilate into your vocabulary. That’s just how people work. The younger you are, the faster the assimilation because there are peak times for learning language in people’s lives, right?
Every piece of my gods stop aging/are created at their peak. That means their language assimilation is at the absolute best it’s going to be 100% of the time. They are going to adapt to the dialect surrounding them fast and consistently. They may occasionally throw an old-timey phrase in there, but because it’s not likely to be in their ready vocabulary, they’d have to be making a conscious effort. They absolutely can code switch, and do in my books depending on who they are speaking to. But even if they weren’t magical beings with fluid intelligence, even if they were completely typical humans who just so happened to be immortal, they may struggle with language barriers, but their dialect would evolve daily.
Secondly, the gods themselves are universal translators. People hear them in their native tongue. Now, hearing someone in your native tongue doesn’t do you much good if you’re hearing them in an archaic version of your native tongue. Ask anyone who has read the Canterbury Tales as it was originally written. That’s English, yet we still have a translated version of it for modern readers. Persephone is a sixteen year old girl who was raised human. So she’s going to hear the gods in her native tongue.