Your Cart and Checkout page can be translated to 51 languages. You can control the language settings in your eCommerce App → Settings → General → Regional settings.
It works in the following way:
A customer will see a language most suitable of all languages enabled by store owner. This language will be automatically set based on customer's BROWSER settings.
If your site visitor is using any of the unsupported languages, then the Checkout page will be displayed on the default language of the store.
Ines from Ucraft Support Team