I had problems at first with the system misunderstanding certain numbers. It does better with words. So I use mostly pre-stored voice tags that correspond to the numbers I call more frequently. When I do have to use the digits command I have learned through trial and error that it is not how loud you say what you say. It is rather the manner that you employ to pronounce the words. Practice. Once you get it it becomes much easier. The convenience is worth the effort.