We are not able to customise error messages for the forms based on the field details. Error messages are hard coded - This answer is required.
Currently, we have multiple language forms for one of our websites. As error message is not customisable, we can’t change English message to another language.
Example URL - https://qh.advancedforms.squiz.cloud/form/metro-south-health--online-feedback-form----persian-farsi If you try to submit form without filling any fields, error message is displayed in English.