Translate property names

I generate JSON schemas based on thy applications metadata (Entity, Properties, Validation-Rules) etc. and then use ajv-i18n to get translated (german) messages out of AJV that get rendered into the otherwise translated UI.

This works great except that I don't see a way to translate the property names. I get messages like:

sollte das erforderliche Attribut firstName enthalten

The word "firstName" is English and should be "Vorname". I have this text already on hand when generating the JSON schema and even when validating.

How can I feed in my custom property name or let's better say "Property Caption" into the messages?

Btw: From PoV there are two things: a) propertyName (technical, internal) and b) propertyCaption (the thing to show to the user/message).