Letters which have a hissing sound; as, S and Z.
53. What letter is called the Mute Sibilant?
The letter X.
54. What letters represent no sound of their own?
C, Q, and X.
55. What are these letters called?
Redundant letters.
56. Why are they so named?
Because they are not necessary for the completion of the Alphabet.
57. By what letters are the sounds of C represented?