Add a dedicated translator guide document

docs/CONTRIBUTING.md

@@ -11,14 +11,14 @@ There are several ways you can get involved:
 | - Support<br/>- Question<br/>- Discussion | Post on the [**Arduino Forum**][forum]                                           |
 | - Bug report<br/>- Feature request        | Issue report (see the guide [**here**][issues])                                  |
 | Testing                                   | Beta testing, PR review (see the guide [**here**][beta-testing])                 |
-| Translation                               | [Transifex project][translate]                                                   |
+| Translation                               | See the guide [**here**][translate]                                              |
 | - Bug fix<br/>- Enhancement               | Pull request (see the guide [**here**][prs])                                     |
 | Monetary                                  | - [Donate][donate]<br/>- [Sponsor][sponsor]<br/>- [Buy official products][store] |
 
 [forum]: https://forum.arduino.cc
 [issues]: contributor-guide/issues.md#issue-report-guide
 [beta-testing]: contributor-guide/beta-testing.md#beta-testing-guide
-[translate]: https://www.transifex.com/arduino-1/ide2/dashboard/
+[translate]: contributor-guide/translation.md#translator-guide
 [prs]: contributor-guide/pull-requests.md#pull-request-guide
 [donate]: https://www.arduino.cc/en/donate/
 [sponsor]: https://github.com/sponsors/arduino

docs/contributor-guide/translation.md

@@ -0,0 +1,33 @@
+# Translator Guide
+
+The text of the Arduino IDE interface is translated into several languages. The language can be selected in the dialog opened via **File > Preferences** in the Arduino IDE menus (**Arduino IDE > Preferences** for macOS users).
+
+Translating text and improving on existing translations is a valuable contribution to the project, helping make Arduino accessible to everyone.
+
+The translations for the text found in the Arduino IDE come from several sources:
+
+## Arduino IDE Text
+
+Translations of Arduino IDE's text is done in the "**Arduino IDE 2.0**" project on the **Transifex** localization platform:
+
+https://explore.transifex.com/arduino-1/ide2/
+
+## Base Application Text
+
+Arduino IDE leverages the localization data available for the [**VS Code**](https://code.visualstudio.com/) editor to localize shared UI text. This reduces the translation work required to add a new language to the text specific to the Arduino IDE project.
+
+For this reason, some of Arduino IDE's text is not found in the **Transifex** project. Suggestions for corrections or improvement to this text are made by submitting an issue to the `microsoft/vscode-loc` GitHub repository.
+
+Before submitting an issue, please check the existing issues to make sure it wasn't already reported:<br />
+https://github.com/microsoft/vscode-loc/issues
+
+After that, submit an issue here:<br />
+https://github.com/microsoft/vscode-loc/issues/new
+
+## Arduino CLI Text
+
+The [**Arduino CLI**](https://arduino.github.io/arduino-cli/latest/) tool handles non-GUI operations for the Arduino IDE. Some of the text printed in the "**Output**" panel and in notifications originates from **Arduino CLI**.
+
+Translations of Arduino CLI's text is done in the "**Arduino CLI**" Transifex project:
+
+https://explore.transifex.com/arduino-1/arduino-cli/

i18n/README.md

@@ -0,0 +1,11 @@
+# Localization Data
+
+This folder contains the [localization](https://en.wikipedia.org/wiki/Internationalization_and_localization) data for Arduino IDE.
+
+❗ These files are automatically generated and so can not be edited directly. If you wish to modify the contents, do it at the source:
+
+- **en.json** - edit the string in [the source code](../arduino-ide-extension/src)
+- **All other files** - the localization is done on **Transifex**:<br />
+  https://explore.transifex.com/arduino-1/ide2/
+
+For more information on translating Arduino IDE, see [the **Translator Guide**](../docs/contributor-guide/translation.md).