Q: How can I set the language of the Cashier interface?
A: The language is controlled by the settings of a shopper's web browser by default. If you do wish to change this, you can set another language by
adding the header parameter of "Accept-Language", or assigning the language value to the body parameter of "language"; the former has a higher priority
specifying the language in the JS code.
The possible options are "en", "fr", "zn", "de", "es", "ar", "ru", and "pt".
For a Cashier widget:
When creating a server session:
Accept language: fr
If both are specified the default language will be French.