A. If each person were the measure of all things, none could ever be taught a language. "Not Orange, Lozenge", the teacher would say. "Lozenge to you, Orange to me," the child would answer.
B. The plausibility of relativism comes from these tautologies: I cannot be told a truth I cannot grasp. To utter at you a truth that you cannot grasp is not to tell it to you.
C. But it could work on myself. Though I cannot grasp a truth, yet I can shower in the stream of its words, until its familiarity makes it into something I am reminded of when I hear the next incomprehensible truth. That's when I'll declare the first understood.