Paragraph 1: Enter what language other than English you are fluent in. It comes from a past tense form of the Latin verb affidare, meaning "to pledge"; in Latin, affidavit translates to "he or she has made a pledge.An affidavit is a written statement made under oath that is typically used in legal proceedings. Learn their purpose, when to use, and how to write. A written statement that someone makes after promising officially to tell the truth. An affidavit can be used as proof in a law court. The affidavit translation process may be necessary if a person who needs to sign an affidavit doesn't speak English. Legal Language Services. Find definitions of legal terms to help understand the federal court system. Appearing before the undersigned notary and being duly.