The man you see above is Leslie Flint, a so-called mentalist who apparently had the voices of dead people talking around him.  This is the best way to describe it, but the page from which we gleaned this topic has its own description:

Leslie hears, when going to the cinema, voices whisper in the dark. He is not the only one; people around him hiss for silence. When this goes on he is forced to leave the cinema. The voices are the first manifestations of the direct voice phenomenon.

He allegedly could summon a number of different people, most of them ordinary folk (and therefore not researchable), but he included a number of celebrities as well:

Diplomat Mahatma Gandhi
Writer/Dramatist Oscar Wilde
Composer Chopin
Actress Ellen Terry

The page discusses all of the attempts that have been made to investigate Flint, including tying him down and gagging him in 1972.

But any results of the tests are mysteriously absent.  Was it a success despite the gag?  Did he pull a "Geller" and claim that his "energy" was too low for a demonstration? 

There is decidedly little on the page about investigations into the veracity of Flint's claims.  The fact that he went on for so long without being debunked seems evidence enough for the believers.

So it looks like we're going to have to make a few conjectures of our own. 

1) Every single one of the speakers on the audio files has an English accent.  Even Bessie, the stereotypical cotton picker from Alabama.  Her accent fluctuates from a lame attempt at an American south accent to British cockney to Scottish. Listen (it will come on automatically) to her recording and see if you don't agree. 

2) Chopin speaks perfect English.  He was Polish, and ostensibly only visited England a few times. 

3)The speakers all have the same basic speech pattern, with little to no deviation between them.  They all talk about the same stuff, about how wonderful it is on "their side."  They all use the same terminology, no matter what time period or part of the world.  Also, the English of 18th Century England is very different from the English of the 20th century, which is something that obviously has slipped Elizabeth Fry's mind. 

Sure, Flint could have been what he claimed to be.  And I could be a Chinese jet pilot.