Original: The round function in Serpent consists of key-mixing XOR, thirty-two parallel applications of the same 4x4 S-box, and a linear transformation, except in the last round, wherein another key-mixing XOR replaces the linear transformation.
Simplified: The round function in Serpent consists of: key-mixing XOR, thirty-two parallel process of the same 4x4 S-box, and a linear transformation, except in the last round, in which another key-mixing XOR replaces the linear transformation.