I also have problems with differentiating between arm and on (I am English). I have used the "add to dictionary technique" which seemed to work successfully when tested in notepad, but still have problems when used in the sim. Could it be that the processor is so busy with FSX that it struggles to allocate sufficient resource to the word recognition? (I admit that I am not an expert in this, but I see that my FSX CPU is bouncing off 100%, is it possible to allocate the speech recognition task to another CPU?) Could changing arm to armed be another option? The D on the end may help the recognition aspect?