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:
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/
Arduino IDE leverages the localization data available for the VS Code 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:
https://github.com/microsoft/vscode-loc/issues
After that, submit an issue here:
https://github.com/microsoft/vscode-loc/issues/new
The Arduino CLI 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: