The word “song” may conjure images of a single singer or group singing together, but songs also can encompass many different musical forms and genres. Whether a song is sung a cappella or accompanied by an instrument (or instruments), it may be a traditional folk melody, a popular song, an art song, or a classical composition. In the Library of Congress, we use the term to refer to a complete song as composed of lyrics and music that is protected by copyright—the melody as a musical work and the words as a literary work.
Our latest research seeks to understand the evolution, meaning, and predictive power of lyrics, examining the relationship between lyrical descriptors and the songs they describe in a large dataset of English-language, Western, popular music that spans five decades and includes several distinct genres. Previous studies have explored the relationship between a particular descriptor or genre and song popularity, but most focused on smaller datasets.
Researchers have found that lyrics are becoming simpler over time, which could reflect a growing trend toward more straightforward music. In particular, there has been a boom in the use of repeated lines of music or lyrics, known as a refrain. Popular hits like Adele’s Rolling in the Deep, Ed Sheeran’s Shape of You, and The Weeknd’s Blinding Lights feature this format.
While it’s not clear why these repeated sections are taking up more space, scholars have noticed that a verse-chorus song form—which is based on the traditional sectional structure of songs—is more common than ever before. This arrangement, which is used in love ballads and other popular genres of music, typically consists of alternating long and short phrases of lyrics followed by a repetitive chorus.