Simplify the following text for a Grade 9 native English-speaking person.
Original: Civilian drum corps were founded using equipment sold off by the military in the early 1900s , and the last official change made to the military bugle ( before its role as a signaling device was rendered obsolete by the radio ) was to standardize them in the key of G. Bugles in other parts of the world typically were pitched in B flat or E flat .
Simplified: Civilian drum corps were made using instruments sold off by the military in the early 1900s , and the last official change made to the military bugle ( before it stopped being used because of the invention of the radio ) was to make them all use the key of G. Bugles in other parts of the world used to be in B flat or E flat .