18. The mobile system according to claim 1 , wherein the speech unit includes a speech coder that converts the natural language speech utterance into the electronic signal, an array microphone that receives the natural language speech utterance, and a filter that optimizes a signal to noise ratio of the electronic signal.
21. The mobile system according to claim 18 , wherein the speech coder uses an adaptive lossy audio compression to convert the natural language utterance into the electronic signal.