Nina Dellinger was 16 when she realized she could read lips.
She was zoning out in math class, she said, and it struck her that she could understand what a classmate was saying across the room, even though she couldn’t hear a word.
For years, Ms. Dellinger kept this skill to herself, practicing in secret in social situations, making it a game. That changed in 2020, when she joined TikTok and found that she could rack up followers by interpreting the whispered, caught-on-camera conversations of celebrities and other prominent people.
At the 65th annual Grammy Awards in February, Ben and Jennifer Affleck appeared to be in the middle of a tense but inaudible conversation at their table. Ordinarily, a celebrity couple’s off-mic conversation would remain a mystery to anyone out of earshot, but Ms. Dellinger filled in the blanks.
In a video she posted to TikTok, she said that the former Ms. Lopez appeared to have said, “Prove it.” Then, after a pause, Ms. Affleck repeated the same thing: “Prove it.” Ms. Dellinger’s video has more than 12 million views.