From what I understand, world building for a story is pre-production work done before story writing happens. Sometimes, it is an activity that happens alongside story writing (world building -> story writing -> world building -> story writing, etc). I think this applies to all writing, not just writing for games. Writing for games is really just a subset of writing.

I'm working on writing the story for my own game. It's a LOT of hard work and planning. The hard part is figuring out what story I want to tell. My current approach is to write the whole story as a novel using discovery writing, then rewrite the story a few times. I figure that between all of the rewrites, each successive story will gravitate towards common plot points that are most interesting to focus on. Once I have the story plot structure and characters well established and have well explored the story space, I'll be ready to adapt it into a game with interactive story telling.

When it comes to writing for games, I think the writing format changes. It'll be structured more similar to a screen play than a novel, and you may have branching plot lines which can be filled out based on your explored story space and alternate endings. Sometimes, the story branches are more cosmetic than plot structural, and generally tend to follow a main story arc -- I actually don't know of any games which have drastic changes in plot structure based on player choice.

I would say that if you want to write, you should spend a majority of your time writing. You're going to suck. You'll produce garbage you aren't happy with. But those are stepping stones towards better work. When you get more experienced as a writer, you'll also get more experienced at world building and have a better idea on what matters and what doesn't matter. You'll always want to focus on your audience experience first as well! You may like inventing new languages which are functional, but will your audience understand, know, or care about it? What's their user experience like?

At the end of the day, whether you're writing books, creating movies, a playwright, making games, etc, we're in the entertainment industry and it is our job to entertain our audiences. Never lose sight of that.

You know, taking down notes of your video game ideas no matter how short it is will help jumpstart your pre-production. Here are my answer to your questions. 

1.  I do believe that writing is necessary for content creation no matter what the medium is, and in this case, it's for video games. I find it essential to write guidelines, structure, descriptions, dialogue for video games. Good writing is where a good story comes from.

2. You don't have to write everything yourself. You can ask your friends to help you out. The important thing is that you have your premise and you do your research. A well-researched content can give your world-building a good foundation. 

3. Of course, it can be used if you will polish and allow it. 

4.  Practice a lot. Do it on a daily basis if you can. Enjoy the process. Once you become really good at it, show some sample of your works. You have to make a lot of connections in order to land an offer. 

5. Yes! It would help you financially and establish a connection with a few clients. 

1. Backstory/world-building is useful for story-driven games and necessary for sandbox games.

2. All of the "advice from professionals" lists that I've seen include "work towards your strengths."  World-building is your strength, so advertise yourself that way and look for projects that need it rather than try to fill some void that's better filled by someone else.

3. Talk to people. ... a lot of people.  Getting the job depends on your skill, but getting the interview depends on who you know.

4.  Invented languages are part of world-building.  Whether or not it's of use to a game depends on the individual game.

5.  It's certainly a paycheck.  Just be aware that if they hire you as a translator, they're -not- hiring you as a writer.

Hi there! I'm new at this forum. Working on a new game, doing all the writing. It is my believe that writing is still important in the game procedure, not because of how much the gamer is gonna read about, but for the unconciouss listening. I mean, it is all the lore behind what makes a game richer. for example, in this new game I working on, the point where the gamer starts playing is completely far away from the point where I started the whole history. And that¡s because I really need to create a complete new atmosphere, with all the past character's, the origin indeed, in order to make everything have sense. Well, timeline is like the line I wanna show to the gamer but only the parts I think the player needs to know in the very moment he is playing.

Obiously, if you are playing a chess game, for example, it is not necessary to write a complete story. But you do realize how important it's gonna be to enrich the game.

Thanks for the thread, it's good to share opinions about this part of the game.

1. You are probably interested in the large-scale writing needed for dialogue and exposition in some game genres, but there are usually titles, captions, option values, and other humble but important things that need to be expressed clearly and creatively. Some kinds of game design, like tutorials or linear levels, are also very similar to telling a story.
2. I'd focus on developing the stories and worldbuilding a game needs (e.g. what medieval fantasy factions would go to war with zombies vs. domesticated wolves) rather than on figuring out what game could fit your worlds and characters.
3. Related to 2 above: show that you can solve problems.
4. A game about figuring out and/or enjoying an invented language is certainly possible, but it is an unlikely niche that, realistically, you shouldn't pursuit. Maybe invented languages can be featured in mainstream games as untranslated found inscriptions, dialogue between foreign characters, and the like.
5. Your spelling imperfections don't inspire much faith in your translation skills, but in a team you are likely to be the only person able to read documentation and literature in certain languages and write or talk to foreign people, which can be very useful.