Sound engineers from Scottish company CereProc brought Mr Kennedy’s voice back to life by synthesising 116,777 voice samples from 831 of his speeches and radio addresses.
The 21-minute long recording was published today and it features the president’s voice, complete with his Boston accent, delivering the 2,590 words he was meant to say in Dallas.
The sound units were analysed for pitch and energy and had to be tested next to each other to make sure they didn’t clash.
Chris Pidcock, co-founder at CereProc in Edinburgh said: “There are only 40/45 phones in English so once you’ve got that set you can generate any word in the English language.
“The problem is that it would not sound natural because one sound merges into the sound next to it so they’re not really independent.
“You really need the sounds in the context of every other sound and that makes the database big.”
This means that the same letter can sound differently when placed next to different vowels or consonants.
For example, in different accents the W sound in “weapons” differs from the one in “words”.
CereProc’s text-to-voice technology can give a voice back to people affected by diseases that are making them lose the ability to speak.
Mr Pidcock recreated Roger Ebert’s voice after he lost it because of cancer using hours of the late film critic’s commentaries.
But he admitted that recreating Mr Kennedy’s one for the “JFK Unsilenced” project proved to be more difficult.
He told The Times, which commissioned the project: “Because of the old analogue recording devices used, it appeared as if it was a different person speaking each time.
“Trying to harmonise the environment and manipulate the audio so that it ran together was quite difficult.
“One of the things we needed to do is get a very accurate transcription of the audio so that things like ‘umms’ and ‘ehs’ could be labeled and we could make sure the phonetic pieces we got were correct.
“If you label them incorrectly you might pick the wrong piece and the whole sentence will sound wrong.”
Mr Kennedy was killed in his motorcade by Lee Harvey Oswald on November 22, 1963 while he was on his way to deliver this speech at the Dallas Trade Mart.