For years, Americans have been putting the squeeze on consonants. We try not to let two consonant sounds touch in a baby name, placing vowels between them. Names like Oliver, Emma and Vivian are in; Orville, Erma and Vernon decidedly out.

But the war on consonants has gone even further: the vowels are cutting out the middleman. More and more, vowel sounds follow one another without any consonant buffer. You can see them in action in America’s top two boys’ names, Liam and Noah. It’s not just about the letters, but the sounds—compare the two syllable “oa” of Noah to the less fashionable single syllable version in Joan. Similarly, the “iya” sound pairing in Aaliyah fills the bill despite the written letter y.

Sounds like these have been slowly rising for generations as fashion has moved away from traditional English names. In this generation, though, the vowel clusters have exploded in popularity. Take a look at the rate of vowel pairings among the top 100 names for boys and girls at 20-year intervals. Above each bar, I’ve indicated how many different names made the popularity cut.

In the most recent statistical year, almost a quarter of the top names featured consecutive vowel sounds. The fresh hits include revivals like Lydia, imports like Mateo, and innovations like Neveah. You can get a feel for the style impact in this list of popular names with different pairings.

That’s the sound of the 21^st Century. It’s worth noting, though, that the few names that take the opposite approach of dropping vowels, like Axl, are also getting some attention. They’re not a return to the world of Orville and Erma so much as an aggressively eye-catching flouting of custom. The age of Mr. Mxyzptlk may yet be ahead of us.