After its release in late 2022, ChatGPT reached 100 million users in just two months, making it the fastest-growing consumer application in history. Since then the artificial intelligence (AI) tool has significantly affected how we learn, write, work and create. But new research shows that it’s also influencing us in ways we may not be aware of—such as changing how we speak.

Hiromu Yakura, a postdoctoral researcher at the Max Planck Institute for Human Development in Berlin, first noticed differences in his own vocabulary about a year after ChatGPT came out. “I realized I was using ‘delve’ more,” he says. “I wanted to see if this was happening not only to me but to other people.” Researchers had previously found that use of large language models (LLMs), such as those that power ChatGPT, was changing vocabulary choices in written communication, and Yakura and his colleagues wanted to know whether spoken communication was being affected, too.

The team’s results, posted on the preprint server arXiv.org last week, show a surge in GPT words in the 18 months after ChatGPT’s release. The words didn’t just appear in formal, scripted videos or podcast episodes; they were peppered into spontaneous conversation, too.

I've noticed that the more I use any given LLM, the more tedious the rigid idiolect becomes. The use of vocabulary generally reserved in conversation for extraordinary events feels shoehorned into more mundane matters.