docs: add info about how to translate stuff #5893

CONTRIBUTING.md

@@ -27,7 +27,7 @@ In case you want to contribute, but you wouldn't know how, here are some suggest
 
 7. **[Make a feature or improvement request](https://github.com/super-productivity/super-productivity/issues/new)**: Something can be done better? Something essential missing? Let us know!
 
-8. **[Translations](https://github.com/super-productivity/super-productivity/tree/master/src/assets/i18n), Icons, etc.**: You don't have to be programmer to help. Some of the icons really need improvement and many of the translations could use some love.
+8. **[Translations](docs/TRANSLATING.md)**: You don't have to be programmer to help. See our [translation guide](docs/TRANSLATING.md) for details on how to contribute translations.
 
 9. **[Sponsor the project](https://github.com/sponsors/johannesjo)**
 

docs/TRANSLATING.md

@@ -0,0 +1,50 @@
+# Translation Guide
+
+Super Productivity uses JSON files for translations, located in `src/assets/i18n/`.
+
+## How to Contribute
+
+1. Find your language file in `src/assets/i18n/` (e.g., `de.json` for German)
+2. Edit the JSON file directly
+3. Submit a pull request
+
+## Important Notes
+
+### Fallback Language
+
+**English (`en.json`) is the fallback language.** If a translation is missing or empty, the app automatically displays the English text.
+
+### Empty Values Are Intentional
+
+When you see empty strings (`""`), this is **intentional** - it triggers the English fallback. Do not copy the English text into empty fields unless you're providing an actual translation.
+
+```json
+{
+  "SOME_KEY": ""
+}
+```
+
+The above will display the English text for `SOME_KEY`.
+
+### File Format
+
+- Nested JSON structure
+- Keys use SCREAMING_SNAKE_CASE
+- Keep the structure intact - only change the string values
+
+### Example
+
+```json
+{
+  "G": {
+    "CANCEL": "Abbrechen",
+    "SAVE": "Speichern"
+  }
+}
+```
+
+## Tips
+
+- Use `en.json` as reference for context
+- Keep translations concise (UI space is limited)
+- Test your translations locally if possible (`ng serve`)