Kory Stamper defines words for a living. In her new book, Word by Word, she documents the life of a lexicographer, from maintaining focus in the office to tackling the near-impossible task of defining English. As she explains in the above video, language is always changing.

She becomes immersed as soon as she arrives at the office. “Once you get in, it’s the sort of thing where you can really go for hours without realizing hours have gone by,” she says. Dictionary writers spend their days combing through examples of English, searching for intriguing word usage or new coinages that might pop up. That can include words that would make a grammar stickler flinch, like “irregardless,” or internet-friendly slang (yes, “facepalm” has been added to the dictionary).

But as Stamper explains, writing dictionaries isn’t just about defining words. It’s about exploring, investigating, and always being just a few steps behind the English language. The dictionary will never be “finished” — and that’s probably what makes it worth writing.