Yes this is totally possible!
You can change the default language shown to the customers side (calendar/form)
Warning
The ability to use Multi-language is part of the Premium plan. The ability to change the main language is free
Steps to change the default language of the Cowlendar calendar and forms (NOT to change thet language in Cowlendar on the admin side of things):
In your Shopify admin dashboard look at the left panel and click on Apps
Click on Cowlendar
Click on Settings
Click on General Settings
Scroll down until you see the multilanguage section
1. Note that if you are on the Free plan you will only be able to change the default language
Set your default language
Warning
Notice what is in German and what is in English in the screenshots below
Warning
Anything custom like service title, description, custom questions can only be in the language they are written in Apps > Cowlendar > Settings > Translation
