How to specify language(s) that an Evidence MUST be provided in?

[jimjyang]

Since an instance of the class cv:Evidence is a concrete piece evidence that the user provides in run-time, and dct:language there is thus used to specify the language(s) in which that particular piece of evidence is provided, how to, in design-time, metadata-specify the language(s) that the evidences must be provided in?

Do we e.g. need a property dct:language in the class cv:EvidenceType?