The TTS client subscribes to the /response topic and converts the response to speech using the sound_play APIs:

    #!/usr/bin/env python 
    import rospy, os, sys 
    from sound_play.msg import SoundRequest 
    from sound_play.libsoundplay import SoundClient 
    from std_msgs.msg import String 
    rospy.init_node('aiml_soundplay_client', anonymous = True) 
 
    soundhandle = SoundClient() 
    rospy.sleep(1) 
    soundhandle.stopAll() 
    print 'Starting TTS' 
 
    def get_response(data): 
      response = data.data 
      rospy.loginfo("Response ::%s",response) 
      soundhandle.say(response) 
 
 
    def listener(): 
      rospy.loginfo("Starting listening to response") 
      rospy.Subscriber("response",String, get_response,queue_size=10) 
      rospy.spin() 
    if __name__ == '__main__': 
      listener()