Nelly Furtado's influences are as diverse as the instruments she plays (guitar, ukulele, trombone), ranging from mainstream pop and indie rock to R&B, hip-hop and traditional Portuguese music.

Collage by Ashley Peña Africa, with its 54 countries and more than 3,000 languages, is not a cultural monolith—and pop music is finally embracing its diversity. In recent years, African women ...