I woke up one morning, in 2001, singing a single line from a hit song at the time. Not the chorus, just one line that caught me: “And on the way I grabbed Soley and Mia.” I sang it enough times that ...

Songwriting can be a personal and revealing process. But for Sóley (last name: Stefánsdóttir), it's an excuse to tap into a separate dream-like world — a world that, until recently, was distant for ...