An affidavit translation is a formal statement sworn under oath. It can also refer to a sworn translation of an official document like a marriage certificate.An affidavit is a written statement that you swear is true and that may be used as evidence in a court of law. The affidavit translation process begins when an attorney drafts an affidavit in English. Paragraph 1: Enter what language other than English you are fluent in. Definitions of 'affidavit'. An affidavit is a written statement which you swear is true and which may be used as evidence in a court of law. A written statement that someone makes after promising officially to tell the truth. An affidavit can be used as proof in a law court. Affidavit definition: .