The present paper shows the work done on 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. It is proposed the use of a screw, coupled to hydraulic transmission, to act on a pullets system on each finger and not keep the motor energized. 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.