I feel sort of out of place, but I consider myself to be an intermediate trumpet player (good for a high school student) and I have developed most of my skills besides tonguing. I have tried Arban's and have been working on it for around 6 months. I've found that I haven't improved much since the first week. I was curious if there is a book more dedicated to multi tonguing or a different method to developing multi tonguing. By the way, my single tongue is sixteenth notes at around 115 or so.