Add wiki section on how to begin a new language (#11756)

docs/Other/Translating.md

@@ -4,7 +4,7 @@
 
 The translation files are at [/android/assets/jsons/translations](https://github.com/yairm210/Unciv/tree/master/android/assets/jsons/translations)
 
-If you're adding a new language, you'll need to create a new file ('Create a new file' to the right of the folder name in the UI), and copy into it the contents of template.properties
+If you're adding a new language, see [Adding a new language](#adding-a-new-language).
 
 If you're adding stuff to an existing language, simply start editing the file!
 
@@ -47,6 +47,18 @@ Some entries have line breaks expressed as `\n`: Your translation can and in mos
 
 Chinese tutorial: 如果你是中国人，那么恭喜你运气不错！这里有Unciv中文开发者们专门为中文翻译工作者准备的（十分详尽）教程视频。：[(Video On Bilibili)](https://www.bilibili.com/video/BV1pY4y1u7WH/)
 
+## Adding a new language
+
+If any of the following steps are beyond your skillset, ask for help. All but the first two steps can be postponed.
+
+- You'll need to create a new file ('Create a new file' to the right of the folder name in the UI), and copy into it the contents of template.properties
+- For automatic language processing for a release (e.g. adding new templates) there needs to exist a line in [completionPercentages.properties](https://github.com/yairm210/Unciv/tree/master/android/assets/jsons/translations/completionPercentages.properties). Location and number do not matter, what matters is that the language name left of the ` = ` corresponds exactly with your new language file name, case-sensitive, without extension.
+- For a nice display in language picker and options, we need a flag. It should be a circle surrounded by transparency within a 128x128px square. Add such a png to [FlagIcons](https://github.com/yairm210/Unciv/tree/master/android/Images.Flags/FlagIcons). For potential sources, look in the [credits](https://github.com/yairm210/Unciv/tree/master/docs/Credits.md), and when done, add your source unless it is already covered.
+- A new graphic needs to be converted into the texture atlases (see [Images and the texture atlas](../Modders/Images-and-Audio.md#images-and-the-texture-atlas)) - for a new flag, this usually means running the desktop version once from source, then uploading the updated atlas files via push or manually.
+- Lastly, your new language should be represented in the [LocaleCode](https://github.com/yairm210/Unciv/tree/master/core/src/com/unciv/models/metadata/GameSettings.kt#L261) enum - reasons see below. You can add this even if you cannot compile - just make sure you follow the existing pattern, and read the inline documentation.
+- The first function of this entry is alphabetical sorting. Unfortunately, it is not easy to tell whether a specific combination is supported by Java. The simplest way to deal with this is trial and error - once your language is established and playable, see if Civilopedia entries seem properly sorted, if not, open an issue and tell us what _other_, more common language may have better sorting rules.
+- This entry is also required to enable fastlane description upload to a correct folder - however, whether F-Droid supports your language is not guaranteed ([this page](https://f-droid.org/docs/Translation_and_Localization/) should help - but doesn't).
+
 ## Why not use a crowdsourcing translation website like <...>?
 
 1. Testing. Currently, translations undergo a number of tests for verification. This allows some language changes to be accepted and others not, and it's all in the same platform with the same tests. External translation tools don't allow for this.