Of all the lines in Guardians of the Galaxy the simple “I am Groot” was undeniably the most memorable, closely followed by “I am Groot” and “I am Groot”. However, it turns out that Groot – Vin Diesel's giant tree-man who’s repeatedly rattling off his own name in the style of a wooden Hodor – is more complicated than you might think.
James Gunn, director of Guardians of the Galaxy Vol I and II, recently revealed via Instagram that Diesel is treated to a secret “Groot version” of the sequel’s script, with all of his “I am Groot”s translated into English to help him capture the right tone of each line.
This was also the same approach in Vol I, as Gunn previously revealed when asked by a fan:
We’ll have to wait until 31 July 2017 when Guardians of the Galaxy Vol. 2 is released in the UK to even guess what Groot is saying. Although he must actually say "I am Groot" once, right?