The FooEvents plugins come bundled with translations for several popular languages and locales which are listed here:
https://help.fooevents.com/docs/topics/translations/supported-languages/
You can modify the bundled translations or create your own custom language files using a free software application called Poedit.
The instructions for creating custom language files and uploading them to your site can be found in this help article:
https://help.fooevents.com/docs/topics/translations/language-files/
FooEvents is also compatible with TranslatePress and WPML, popular WordPress multilingual plugins that let you translate your website content into multiple languages.
The FooEvents Check-ins app can be used in the following languages:
https://help.fooevents.com/docs/frequently-asked-questions/check-ins-app/what-languages-does-the-fooevents-check-ins-app-support