Content Validation - How to exclude special characters in Text entry questions

I am preparing a survey where the user will type the surname - text question.
I want to make sure that characters such as accents, apostrophes, umlauts are not accepted.
I cannot see, under content validation options, a way to exclude special characters
Am I missing something? Has anyone who had similar requirement found a way to do the above in Qualtrics?
Many thanks
Anna