Lee “Mixashawn” Rozie is a multi-instrumentalist who fuses jazz with the music of many cultures, especially Indigenous people. His latest work, An American Songbook, gets its world premiere Saturday in West Hartford. The title may be misleading to some. Rather than a celebration of popular music from the first half of the 20th century, Rozie’s interpretation of the phrase is quite literal. “The word ‘American’ is so misunderstood,” said Rozie. “When I say ‘American,’ I am thinking of all the