YES - The relevant authorities are entitled to ask you to take a language test. However, such rules should be applied in a proportionate manner and exceptions should be possible, in order to take account of individual circumstances - for example, if you have lived or worked in a country using that language.
POSSIBLY - Recognition of academic qualifications is the exclusive responsibility of national governments. The European Commission can only intervene if:
The ENIC-NARIC centre in the host country (a Europe-wide academic recognition network) may be able to help by contacting its counterpart in your country.