One noticeable things about this performance, and indeed most of them, is that whenever there are vocals, they tend to be in English. Why is this? Is it because the original songs were in English? Or is it because, if you compose a jazz or blues song, then English is the natural language to do it in?Maybe it's a bit like opera, which is mostly in Italian (though Mozart broke this mold by composing his later operas in German, and Wagner used German throughout). English seems incongruous for operas, except for the comic operas of Gilbert and Sullivan and some recent work by composers such as Benjamin Britain.
Why should one language be appropriate for a musical genre and another language seem wrong? Is it something to do with the rhythm? That can't the the answer, as English and German have the same stress-based rhythm, so there should be no difference in choosing between the two languages.
Maybe it is just the level of expectation. So much of art is what you are used to, what is familiar, and if you are presented with something that goes against those expectations, it just does not seem right.
