The program works, but does not always listen to the command, so I have to repeat the command a few times, and especially the Stop command, I sometimes have to repeat it several times.
Can someone help me
Sometimes using two word commands works better when using the SpeechRecognizer than single word commands. Perhaps try go right instead of right; go left instead of left ? please stop perhaps rather than stop. 
What happens when you use two or more word commands like in the tutorial below? With my Android doing this allows the SR to know what to expect much better than a single word. 