Lee DeForest announced the development of the first "triode", or three element detector tube in 1906. His initial efforts at broadcasting voice were frustrated by the earlier spark-gap technology in use at the time. DeForest sold the US commercial patent rights to ATT in 1914, the same time that the first voice transmitters began to appear.
The initial utility of radio was to have the ability to communicate where wires could not go. Shipping and maritime uses were first, followed by public broadcasting of voice and music.