How do I cancel Babbel

It sounds like the App is not billed through Apple, in that case:

Get help with subscriptions not billed through Apple

"Learn which subscriptions are billed through the iTunes Store or App Store, and how to get help for subscriptions that aren't billed through Apple.

You might be billed for a recurring subscription through Apple or through another company, which is sometimes referred to as a "third-party subscription." If your credit, debit card, or bank statement lists iTunes or Apple, you can use your Apple device to view, change, or cancel your subscriptions.

You might have purchased some subscriptions through another company, including:

• Content or services purchased through a website (streaming video and music services, dating apps, etc.).
• Content or services purchased through an app on another company’s platform (like signing up for Netflix through the Google Play store).

Apple doesn't handle billing and membership changes for subscriptions that you purchased outside without using your Apple ID. Steps to change or cancel third-party subscriptions vary based on the app developer.

If you want to make changes or cancel third-party subscriptions, you might need to sign in to the company’s website."

Follow the advice given in: View, change, or cancel your subscriptions - Apple Support

Try using: Contact Apple Support

When I use that link, I get:

...and then click on "No Thanks. Continue," I get:

That link will not lead directly to a "cancel option," but should provide you a route to contact Apple.

You are welcome.