PretzelBoy
Villager
Things you could (but you don't have to) use languages and/or dialects for in a RPG:
The super-geeky part would be coins. They could be more just pieces of metal. They could have like some symbols or encravings on them suggesting different mints, rulers, eras, city states, metals even. "Ah, you are paying in two-hundred-year-old coins, just like the other person two weeks ago."
- Provide characters with a spoken identity. People can spot a dialect pretty quickly and in many cases determine where the speaker is from (or at least where they are not from).
- To pass as a local/native speaker of a dialect could turn out to be useful in social encounter. Boom! A non-combat problem solving skill test! Deception? Performance?
- This does not have to be a huge piece of homework. You can use a broad brush without going into specifics: If people do not listen to any continent-wide radio stations and do not travel very far beyond the closest market town, the inhabitants of a valley might start to sound different from the people in the sparsely populated uplands or the densely populated coastal area. Boom! Local cultural variety in a sentence! And any native speaker would recognize the difference.
- When a speaker has an identity in their speech, it could become a lead: "What did they sound like? Were they from around here? What kind of a foreign accent?" A mystery: "Oh, you'd better watch out for 'em river folks!" Or a late warning: "You done taken a wrong turn".
- If you happen to have any sort of social classes in your game, people of different status might use noticeably different words and sounds broadcasting their background. Again, it does not need to become a great piece of homework, but simply something that could be used to foreshadow, explain, perplex, hint, or suggest.
- Provide a meaningful motive for cultural variety. If you are running a geographically widespread campaign, you could encourage players choose different cultures or birthplaces providing them with slightly different proficiency in languages and/or dialects. Much like character height or hair color, it does not need to become a focus of the game or does not need a rigorous system around it. Yet, tall people can usually reach higher than non-tall.
- This minor variety may give players slightly different feel for the situation based on what they know. A player character from the coastal area might recognize the tradesman speaking in "wrong" dialect. Boom! A mystery! And a player feeling special without an inflated set of "special abilities". And the players learn that there are these things in the world that you could maybe figure out, that could maybe have meaning, that could be reasoned about, that could be used to divert or could be used solve problems. In story-telling parlance, it's kinda showing things about the world instead of telling.
- The Fellowship of the Ring was one such multicultural group, although the benefits were poorly recorded by the person least knowledgeable of languages. Boom! A Joke!
- Provide a sense of mystery and in-game problem solving, when the player characters embark on a quest beyond the areas familiar or known to them.
- Differences provide a sense of differences. (How about that for a true statement?) If your game has cultures, you could suggest how the other culture sounds a bit different to the player characters. I suppose it has to do with that verisimilitude.
- For a period, the players might not have a complete understanding of the situation around them. Maybe they could hire interpreters to make non-stakes social encounters run smoothly. With the interpreter, the GM could "do exposition" on the political or economic situation that the PCs would otherwise have difficulty of learning. Or, an interpreter could have connections that could help the player characters in their quest (for a favor or two, perhaps). And suddenly, the game is knee-deep in local politics should that suit your fancy. Boom! A side-quest!
- Foreign surroundings could be a motive for language acquisition. Again, it does not need to be huge piece of homework. Does the system support it? If not, you could wing it! Gradually, the player characters could develop skills to "read" the foreign surroundings or even to pass as a local. You could make the aptitude of language acquisition INT-based: a cheap way of making some a characters appear special. Boom! Adventure down-time content!
- With some non-player characters able to exchange ideas in a language not immediately accessible to the player characters, you can turn a letter, an engraving or a symbol a puzzle for the players to solve. They might not be able to solve it themselves, so they might need help. Boom! A social encounter! And through somebody learning about this puzzle, the GM has a venue to "do exposition", increase the stakes, pick up the pacing, dial up the mystery or whatever makes the game more fun.
- Translating an important text in a foreign language might itself turn into an adventure requiring non-combat skills. What language it is, who could translate it, where is it from, how old is it? Boom! An adventure! "Why was this note written in language X of a rival power?" Boom! A mystery! All these questions leave social bread crumbs that the player characters could follow (if they are pursuing somebody closer to the MacGuffin) or the antagonists could follow (if the players are closer to the MacGuffin). Boom! An intricate chase sequence!
The super-geeky part would be coins. They could be more just pieces of metal. They could have like some symbols or encravings on them suggesting different mints, rulers, eras, city states, metals even. "Ah, you are paying in two-hundred-year-old coins, just like the other person two weeks ago."