The present paper shows the work done on part of the design of a robotic humanoid arm, whose objective is to perform the transliteration of sound language, commonly used, to sign language, used by people with hearing disabilities. Through a dynamic analysis it has been obtained the necessary torque for each joint in the arm to perform the correct movement of the servo motors. In addition to this, a script has been made in order to do some tests for speech-recognition and an Android application as a tool for an easier way to process it. For the control of the finger, it was designed an optimal nonlinear controller, which has as state variables the angle and the angular velocity, aiming only to the manipulation of the angle or position of the DC motor, for the purpose of an appropriate movement of the fingers.