Guys as you know there is a glitch on the sound; you drag the bar to the % you want but then after 2 seconds it goes to 0% again. Here I read that the problem was solved by using the phone's volume buttons, but it didn't work for me (it goes to 0% again). Any idea on how to solve that?

Oh, I also discovered the right folder for the voices ... but can't really test them because of the sound problem I've just mentioned. The folder for the voices was "storage/extSdCard/Garmin/" (there it goes the "voice" folder). Again, it confused me that inside the internal phone's memory (called sdcard) there was a folder called external_sd..... it couldn't possibly be any more confusing than that.