Ayo wicked! I wish you the best of luck making a version for other languages.
Since you asked, my development ideas/philosphies for the mod was as follows:
1) Make a spreadsheet of every letter and when it becomes available/easily accessible. E.g. at the start of the game, F is available but not easily accessible, since it requires fish. After simple oil refining, F becomes fully renewable. This guide will be insanely useful for planning things out.
2) Ensure that it's possible to progress to letter decompiling. If it's not, you'll need to do something a bit quirky to make it possible. This is why the spoilage item exists: it's only there because it's the only way to get G for a steam engine and getting power set up.
The reason letter decompiling is so important is because it's the tool I use to allow the players to get letters they need to progress without giving an easy way to get it early-game. E.g. a Y is required for the first oil refinery, but there's no source of it without letter decompiling. In a similar vein, letter decompiling can provide a renewable (albeit very slow) source of previously non-renewable letters like F, G, and H if they are frequently used (e.g. for assembling machines).
3) Science pack names should use the letters that the previous science pack's technologies made become easily accessible. As an example of this, green science unlocks fluid handling, which lets W, D, M, and G all become renewable through water, crude oil, and petroleum gas barrel decompilation. Hence, blue science is "Wordmonger" to use all of these letters (while still being on-theme!). Every letter should be used in a science pack by the end of the game.
4) The letters that cannot be gotten from any resource need special handling to ensure they're acquirable. It's through sheer luck that Q from liquefaction and X from kovarex work as well as they do. I couldn't find any way to fit J in, and they're needed for pumpjacks, so I made their primary source be from letter decompiling. This had the (once again lucky) side effect of requiring the player to build a proper letter recycling plant before blue science.
5) The entire mess that is uranium processing in this mod is from me frantically trying to balance around depleted uranium fuel cells being able to be transmogrified back into uranium fuel cells, which allows for extremely easy infinite power starting from blue science (not good!). These sorts of crafting loops are the absolute bane of my existence from a balancing point of view, and rather than trying to fight against them, it's better to introduce tradeoffs.
E.g. the infinite fuel loop is embraced, but it comes with the tradeoff that it still requires steam from steam engines (at least until endgame), and if the player does the infinite power loop, then they aren't getting the uranium for yellow science.
So, for other languages, uranium might be normal, but there may be other loops that will need to be considered. And it's fine to just not allow certain things to be decompilable, even if it's not ideal. Like, I had to make science packs be unable to be decompiled because I couldn't find a way to avoid infinite science loops from decompiling and recompiling partially-used packs.
6) Always make crafting recipes simple when possible. So, for example, instead of FAST INSERTER, do FAST + an inserter item. This reduces the amount of letters needed for each individual recipe, and has the added side effect of making actual crafting chains.
As an aside, basically every recipe in the game can be simplified this way, so uhh yeah it's not super feasible to just generate all of them with a script. Good luck!
7) In certain rare cases, it is better to change the name of an item outright to make things fit together better (e.g. Assembling machine 2 was changed to fast assembling machine to not lock it behind uranium). This is kind of a last resort though.
8) This mod is silly. Embrace the silliness (e.g. storage tanks requiring tanks to craft).
9) Playtesters and player feedback are your best friends. So many problems I had to fix weren't things that I even thought about.
This ended up being a bit more rambley that I was anticipating, but hopefully I covered all the big things. If you have any questions, I'm always down to answer them (a busy uni schedule means it might take me a bit to respond though >w<). I wish you good luck in creating something awesome! ^w^
