It is really necessary for those documents that have been issued by foreign authorities in foreign language and which will be used in turkey to be translated into Turkish by sworn translator and also attested by notary public.
As it is necessary for the culture of the country in which the document was issued in its language to be known by the translator. Otherwise, some problems could happen. Especially for the clients who don’t have any background about the targeted language they could have some problems eventually the documents could be rejected by the authority to which the documents are presented.