How does the Fifth Amendment protect against self-incrimination?

the Fifth Amendment encompasses this right: '[The Fifth Amendment's privilege against self-incrimination] is fulfilled only when an accused is guaranteed the right "to remain silent unless he chooses to speak in the unfettered exercise of his own will." . . . The choice of whether to testify in one's own defense . . . is an exercise of the constitutional privilege.' [Citation.]" (Rock v. Arkansas (1987) 483 U.S. 44, 51-53, fn. omitted.)

b. The Need for a "Timely and Adequate" Demand to Testify