To say what one thinks. The idea of putting the mind’s contents in words is probably ancient, but the expression is first seen in Shakespeare’s works, as, “Give me leave to speak my mind” (As You Like It, 2.7). A synonym is to speak one’s piece, which transfers piece in the sense of a recited passage to the expression of an opinion. It dates from the mid-1800s; C. F. Browne wrote in A. Ward: His Travels (1865), “I have spoken my piece about the Ariel.” From the same period we have yet another equivalent, to have one’s say. George Meredith used it in Richard Feverel (1859): “Lobourne had its say on the subject.”