Groot is one of the most unique creatures in the cosmos, only able to say three simple words: I am Groot. So, it’s pretty easy to assume that Groot is his name because, well, he’s basically always introducing himself. However, that’s just how Groot’s language works, and for the most part, only Rocket could ever really understand what he was saying. Then Thor came along and threw a wrench into the works.
Article source: https://www.cinemablend.com/news/2465024/was-groots-real-name-revealed-in-avengers-infinity-war-fan-theory-takes-root