All three terms share a Latin ancestry, but only mea culpa (through no fault of its own) retained its original Latin pronunciation when it moved into English. The pronunciations of indict and subpoena have their own tales to tell, and the legal applications of all three words are worth exploring.

Indict was originally (back in the 14th century) spelled "indite." Scholars altered the spelling during the Middle Ages so that the word's spelling would more closely resemble that of its Latin ancestor indicere (meaning "to proclaim"), but the "c" was never pronounced.

The English subpoena (from the Latin sub poena meaning "under penalty") dates to the 15th century. The "b" in subpoena is usually silent, and the variant pronunciation \suh-pee-nee\ draws criticism.

What are the legal applications of indictment, subpoena, and mea culpa?

In Latin, mea culpa translates as "through my fault." The English mea culpa is "a formal acknowledgment of personal fault or error," but that term has no formal place in the U.S. legal system.

Indict indicates a formal accusation in or as if in holding for trial; the Collegiate Encyclopedia notes that indictment is one of three principal methods of charging offenses in the U.S. (the others being the information (a written accusation resembling an indictment, prepared and presented to the court by a prosecuting official) and, for petty offenses, a complaint by the aggrieved party or by a police officer.

The legal subpoena names the writ commanding the person upon whom it has been served to appear in court or before a congressional committee, grand jury, or some other body, under a penalty for failure to comply. As you would think, the legal writ begins with the warning "under penalty." And, unlike a summons, a subpoena may command the recipient to produce evidence necessary to the resolution of a legal matter or controversy.