“Oral” is a song Bjork composed more than 20 years ago, but it never worked for any of her albums. She came upon the composition earlier this year, around the same time that a critical report was published about the devastating impact salmon farming is having on communities in her native Iceland. So “Oral” became the featured song, performed by Bjork and Spanish superstar Rosalia, in a campaign to help Icelandic towns whose economies are suffering.