This version of Somewhere over the Rainbow has become the definitive version of the song. In many ways what Big Izzy has done is fuse the feelgood rhythmn and chords of Bob Marley's 'No Woman No Cry' with a timeless popular jazz song.
To play this song is deceptively hard. Two things you need to focus on are a rock steady strum and to sing what Izzy sings. Easier said than done especially keeping the singing going at the end of each line
Having sung this song a fair few few times in classes and at gigs I have always been aware of taking quick snatches of breath to make the vocal lines last. Also be aware that the range of notes in the singing are quite extreme from high to low but you need to try and make them sound smooth and even. This is the real genius of Izzy's performance on this track as he makes it sound effortless.
This video is for the shortened version of the song ( much better I think) as he added another section to the song with the chorus of 'What a Wonderful World' and it would go on for days. Good Luck Jake !