Interest in EVP apparently began in the1920s. An interviewer from Scientific American asked Thomas Edison about the possibility of contacting the dead. Edison, a man of no strong religious views, said that nobody knows whether “our personalities pass on to another existence or sphere” but
It has been said that Thomas Edison was working on an EVP device. However the credit for discovering EVP goes to Fredrich Jurgenson when he was recording bird sonds in the Sweedish countryside and on play back he distinctly heard the voice of a man discussing nocturnal bird songs in Norwegian. He had heard nothing during the recording but many voices on playback, some giving him instructions on how to record more voices. EVPs are also called Raudive Voices after Konstantine Raudive who recorded 100,000 voices. He published "The Inaudible Made Audible". EVP research is done all over the world but most heavily in the United States and Germany. The Association for Voice Taping Research was founded in the 1970's in Germany, and American Association - Electronic Voice Phenomenon in 1982.
The voices take on diverse forms; they may appear to be speaking in tongues (polyglot), singing or making public service announcements. They interrupt standard radio broadcasts, and can apparently call on by name, and speak directly to researchers (and most likely attempt to communicate with people too busy to notice they are being addressed by the voice of weirdness). They may make themselves heard over telephones, during television broadcasts, and as anomalous interference on tape recordings. Some of them seem to enjoy engaging in dialogue, answering questions, or willingly supply secret, or highly specific personal information, no doubt as an indication of their greater insight.