It’s hard to pinpoint when the QWERTY became the most significant keyboard in contemporary music, but pop’s strange relationship with the shift key has mutated from a trend into a practice. Taylor Swift likes to type out her song titles in all lowercase letters, “like this.” Lil Nas X prefers them in all caps, “LIKE THIS.” On her latest album, Willow Smith — who performs as WILLOW, mononymously uppercased — is getting the space bar involved, too, which means that some of her song titles look “l i k e t h i s.”

If there’s a consensus explanation for why our playlists and pop charts now look as typographically gonzo as our messiest group texts, it’s generational: Today’s stars are 21st-century digital children who grew up expressing their multitudes by tweaking the keystrokes in their text messages, social media posts and more. And this isn’t exactly kid stuff anymore. All of the songs on Kendrick Lamar’s Pulitzer Prize-winning 2017 album “DAMN.,” were titled with single words, every letter capitalized with a period at the end of each word. By simply showing us the album’s track list, Lamar was framing his music as something declarative and decisive. Our eyes were listening before a sound touched our ears.

And yes, these stylizations may have seemed superficial and annoying at first, but now that we’ve stared at them long enough, our listening experience is beginning to change — and in ways that vary from artist to artist, song to song. For instance, Billie Eilish’s lowercase song titles might underscore the delicate intimacy of her singing, while Swift’s tiny letters telegraph modesty, humility and down-to-earthness. For the caps lock crowd, a sequence of big, blocky letter-shapes can feel triumphal, or boisterous, or rude, or needy.

Or, in the case of Lil Nas X’s debut album, “MONTERO,” all of the above. After the history-making success of “Old Town Road,” the Atlanta native is still learning how to close the gap between his massive persona and his developing songcraft, which means the big-lettered tunes on “MONTERO” run the gamut from totally anthemic (the title track) to somewhat anemic (“VOID”). But Lil Nas X obviously knows how to stand out in a digital crowd, so on the major streaming services, where all the fonts are uniform, his uppercase song titles perform a function: HEY, OVER HERE.

Before the streaming era, artists liked to pinch and twist the letters in their names, using their album covers to posit themselves as rebels, rule-breakers and typographic scofflaws. In the 1980s, k.d. lang emerged as the e.e. cummings of cowpunk. In the 1990s, OutKast had that capital “K” while Eminem and Korn occasionally reversed certain letters in their monikers for kicks. In the aughties, indie fans experienced an all-caps-no-vowels craze — MGMT, MSTRKRFT, SBTRKT — as well as the sadistic alt-capping of tUnE-yArDs, which, thankfully, was not communicable.

More recently, scores of rappers have taken stage names that seem like they were never meant to be uttered out loud in the first place. The most vexing in the lot — XXXTentacion, 6lack — felt more like screen names, or maybe even like echoes of Prince’s famously unpronounceable glyph, which, in hindsight, may have been the Artist’s attempt at stripping his identity of a vocalized sound. When we thought of Prince, he didn’t want us to hear the word “Prince” in our mind’s mouth. He wanted us to hear music.

Stylized song titles can help us better hear a song inside the silence of our own consciousness, too — as with Olivia Rodrigo’s debut album, “SOUR.” It’s the big, shiny, breakout pop record of 2021, and Rodrigo’s stylizations play their part, performing an artful little rope-a-dope: With the album’s title in all uppercase, but the song titles uncapitalized, Rodrigo urgently beckons us to come over and check out the tiny treasures she’s holding in the palm of her hand.

One of them is “drivers license,” a vroom-vroomy power ballad that spent eight consecutive weeks at No. 1 on the Billboard Hot 100 this year, its layered metaphors capturing the painful teenage sensation of not being able to control the direction of the road in front of you. In this song, and in most of the songs on “SOUR,” Rodrigo’s singing feels attentive, detailed and highly alert, communicating broad, chaotic, teenage emotions in an elegant, lowercase, teenage way.

Then there’s “t r a n s p a r e n t s o u l,” the opening track on WILLOW’s new album, “lately I feel EVERYTHING.” The song itself is a taut and propulsive rock-like thing with professional punk drumming services provided by Travis Barker of Blink-182. But throughout, WILLOW’s voice remains loose and yearning, like she’s trying to steady herself to that beat. Suddenly, those wishy-washy spaces in the song’s title reveal a surprise tension, like the letters are being pulled back together instead of drifting apart.

So to recap (sorry), the spacing helps forge your expectations of the song, but then the song only half-fulfills them, so your eyes start to hear the song title differently, which makes your mind feel the song differently. c o o l .

Like Rodrigo and WILLOW, Eilish does similar mixing-and-matching on her excellent new album, “Happier Than Ever.” Nearly everything on the track list adheres to the common rules of capitalization, save for one all-lowercase entry (“my future”), and two in all caps (“GOLDWING” and “NDA,” the latter of which is an acronym, so it doesn’t really count). And that’s a shift from Eilish’s 2019 debut, an album of all-lowercase songs that seemed eager to perform a terrific metaphysical trick, quietly drawing us into their whispery verses until we were so close, the music felt colossal. Her smallness became a closeness which became a bigness.

In 2018, when Billboard magazine asked type designer Chank Diesel about the lowercase trend sweeping across pop music, he seemed to be predict the sensation of listening to Eilish: “The lowercase letters are smaller, which ‘sounds’ softer on my eyes, but the lowercase letterforms also have more curves and circles, which creates a more tuneful collection of shapes.”

That’s Eilish. She doesn’t make harsh, brash, right-angled, all caps music. Her singing has fluid contours, liquid details, tight curves. So what to make of her return to traditional capitalization? Probably this: She’s already taught us that she’s worthy of our closest listening. No need to keep spelling it out.

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