The “song of the summer”—the one that’s dominated radio and the pop charts—is “Despacito” by singer Luis Fonsi. More than a simple catchy song, it’s making history. Here’s a look at the song all the kids these days are into. “Despacito” is the first song in the musical genre called reggaeton to hit #1 in the U.S. It’s a fairly new style, originating in Puerto Rico in the 1990s. It combines elements of American hip hop with traditional Latin American music. Reggaeton singer Daddy Yankee is known as the “King of Reggaeton,” and he makes an appearance on “Despacito.” “Despacito” is the second song performed primarily in Spanish to top the charts. The first was “La Bamba.” A Mexican folk song popularized by the late Ritchie Valens in 1958, that version hit #22. Los Lobos’ cover of Valens rock n’ roll version, recorded for the Valens biopic La Bamba, hit #1 in 1987. Because it’s the rare song sung in a language other than English to become a huge hit in the U.S., it’s tempting to...