Imagine two nations, as powerful as they are stubborn, "horns locked" across miles of no man's land: a strip of densely populated wasteland that carves across the map like a meandering river.

A generation ago, two proud armies clashed in epic battles and bloody skirmishes, contorting the front into serpentine lines. But for every gain, a loss, with no side capable of decisive victory. As armies entrench, tents turn into hastily timbered habitats, crowding against one another along miles of ramshackle slums. Forests melt under axes from both sides and become fortifications, opening new land in need of defense.

Across huge swaths of ecological disaster, the Perpetual Front takes shape.

(OPTIONS: high / low / no magic... human / monsters / Lovecraftian horrors ... Set it in Faerun and make it easy ... steampunk ... historical / fantastic ... )

RULES: Probably a given that you, Ewy and I would use the DnD 5e ruleset, right? KISS principle (Keep it Simple, Stupid!)

CHARACTER CREATION

LEVEL 1
"Fish out of water" linguistically, our PCs have "crossed the lines" and now must struggle to learn the language of their cultural enemies in order to achieve their goals.

(really the rest is details... 27 point buy, 4d6 drop 1, humans or drow elves or ithilids... )

Possible hooks / starts :

1. Prisoners
2. Spies
3. Squires that lost their way
4. Charlatans looking for easy profit
5. Romeos looking for forbidden Juliets
6. You get the idea, there's lots of "low hanging fruit" here

LEVELING

XP is not a thing. Instead we use milestone leveling. As players, we set LINGUISTIC GOALS that are keyed to PC GOALS (by the DM and player working together). When the player meets their linguistic goal ("I want to know how to talk about food at a restaurant" or "I want to know how to tell someone to go fuck themselves in the ear"), their PC is ready to achieve their personal goal, and then the PC levels up.

The DM provides roleplay situations that give the PC a chance to practice their goals.

By the time we are level 20, we will have improved our respective language skills by 19 goals. COOL!

SESSION STRUCTURE

We each spend half our time being DM and PC each session. Thus, we will have two parallel PC storylines going on on opposite sides of the front.

As Dungeon Masters, we play the sprawling armies and many NPCs in our respective native languages. We strive to create NPCs that use the language the other player is trying to learn. We have fun with it and flex our RP muscles.

Uh... I could go on, but I think I'll breathe, sleep and let you or others respond now.