Can’t remember if I linked this before or if it’s ever been linked. It’s a recording of Johnson speaking in regards to his fight against James J Jeffies. I get a bit of kick out of this type of historic stuff. Just press the “Sample” button to play. [url]https://www.storytel.com/sg/en/books/a-rare-recording-of-boxer-jack-johnson-426838[/url]
I wonder whether the medium influenced the delivery, i.e., about so-much to speak, and so-and-so minutes to a recorded side, so you wanted the record to look like it was 'full' of Johnson commentary, so perhaps he was encouraged to stretch it out? Also, Johnson might have been more used to unamplified oration, using more space to maintain intelligibility (though I don't think that alone would fully account for the delivery). He does sound to have had a very fully and resonant orating voice.
You can compare it to his speech when he sparred with Joe Jeannette for War Bonds in WW2 .The speech pattern is similar.
Interesting considerations. Possible also that the medium and/or the device it was played back on distorted the delivery - similar to old films that made people everyone move like Charlie Chaplin. As @mcvey stated, it sounds very much similar to Johnson speaking at the 1945 War Bond Rally - only that much slower - perhaps deliberately slowed using modern tech so as to be more intelligible? Or, as you said, simply Jack speaking very slow deliberately so as to be very clear. Notably, while Johnson did have a lisp, it was slight. He was a well spoken, well metered and articulate man. The racist media of the day obviously exaggerated his lisp and downgraded his vocabulary for derogatory purposes. I hadn’t confirmed when exactly the recording was made. I found this interesting article and it seems to point to the recording being made in 1910 - very early days of sound recording. It states that Johnson was asked to make several different recordings - including in 1914 re Physical Culture, after the Moran fight. [url]https://blogs.bl.uk/sound-and-vision/2018/06/the-voice-of-jack-johnson-heavyweight-boxing-champion-of-the-world.html[/url]
Well, amazing what you can find when one rare find leads you to another. Here is some more background on the Physical Culture recordings Johnson made in 1914 - and it describes some technicalities of the recording procedure and Johnson’s delivery style. Fortunately, it seems 1 copy of the original Physical Culture recordings still exists. Okay, I tested and the link in the post reads as if broken but it’s not. If you copy the URL below into notes on your phone - then click the link copied into notes, hopefully it will take you there. What a pain in the ***! Lol. This content is protected [url]https://peckhampeculiar.tumblr.com/post/169995079095/when-jack-came-to-town/amp[/url]
About distorted audio - I read that if you want to listen to the way Robert Johnson actually sang you’d need to play it at 1.25x or 1.5x I forget. It had something to do with the way it was recorded, could be similar.