Jokes aside, it’s great learning that James Gunn took the time to write out meaningful dialogue for Groot, rather than jus those infamous three words across the screenplay.
The only one who’s able to understand Groot is his buddy Rocket, and who knows how long it took him the peculiarities of that language.
Although it hasn’t been addressed in the movies, Groot is a member of the alien species known as Flora colossus, all of whom communicate using those same three words: “I am Groot.”
However, much like Chewbacca’s growling in the Star Wars movies, those words mask what is supposed to be concise and elaborate dialogue, just like a human would say.