So, it looks like your characters don't want to be part of the current time period. It's time to do your research.
What era are they from? When you figure that out, next is coming up with the proper speech. The dialogue has to match. A little understanding of the language and clothing they wore can go a long way in your story. Keep notes on the language, clothing, what they did to pass the time, major events that happened then or could happen (if your character is in the future).
If they've evolved with the times, that can be a bit easier, but research is always necessary. Don't be afraid to dive in and let your character tell you what they want, you can always go back and clarify later. It's exciting either way to do a period piece. Showing a new perspective on a society that many are not aware of. It's amazing to be able to show a new side of time that your readers don't know about or showing them a whole take on the world in general.
Tiffany Heiser is the owner of Tiffany Heiser Graphics & Fyre and Brimestone Publishing. She is a self-taught graphic artist, an author, publisher, & a loving mom.