It can be inferred that Thor's god-like status must give him a linguistic advantage then, as he proficiently understood Groot's language shortly after first meeting him, while most of Groot's teammates remain incapable of comprehending him without assistance.
But one godly connection might technically give one of Earth's Mightiest Heroes an unlikely brother. The revelations about Phoenix and Gaea in Avengers 1,000,000 BC #1 (by Jason Aaron, Kev Walker, Dean White, and VC's Cory Petit) suggest that Thor might actually be brothers with Groot of the Guardians of the Galaxy.
Audiences may have assumed the case of mistaken identity was the result of some combination of Thor's indifference and his preoccupation with defeating Thanos. After all, he didn't bother to call Groot by his real name either, settling for "Tree" instead.
For example, Thor can understand what Groot says upon first meeting the tree-like creature. By the start of the final installment of the Guardians trilogy, all the main characters except Gamora can understand Groot, and by Guardians of the Galaxy 3's ending she learns as well.
Avengers Infinity War | Thor can speak Groot | 1080p
Why can Groot say I love you guys?
Towards the end of the Marvel Cinematic Universe sequel, Groot says, “I love you guys” — a departure from his usual dialogue of “I am Groot.” James Gunn has confirmed that this isn't actually Groot vocalizing the words “I love you guys,” but rather, the moment signifies that the audience has spent enough time with the ...
Being consumed by Groot allows Star-Lord the opportunity to fully understand what Groot is saying as a part of his mind - just as Guardians of the Galaxy vol. 3 finally had the Flora Colossi be understandable to the audience.
Thor's hammer Mjolnir was defined by the fact that only the 'worthy' could lift it – so basically no-one except the god of thunder (and Vision, for some reason). But when it comes to the weapon's replacement, Stormbreaker – which Thor forges in Avengers: Infinity War – Groot is able to lift it too.
In a moment of selflessness, Groot sprang into action and created a handle using his own arm. While it did save Thor's life and complete the weapon, Groot's sacrifice left a strong influence on Stormbreaker's personality, as disclosed by Thor 4's director Taika Waititi at a press conference attended by CBR.
During a Vudu Viewing Party for Avengers: Infinity War, co-directors Anthony and Joe Russo revealed a key difference between Thor's hammer Mjolnir and his new ax Stormbreaker: the latter doesn't require worthiness. That's why Groot was able to lift the ax, not because he was worthy but because he didn't need to be.
In Thor: Love and Thunder's ending, Love carried it into battle alongside Thor, who was once again wielding Mjolnir. The movie doesn't explain Thor's motivations for giving up Stormbreaker, but it makes sense that Chris Hemsworth simply wanted Love to have a powerful weapon to aid her in battle.
Both weapons also appear to have a degree of sentience, with Stormbreaker apparently being envious of Thor's affection for Mjolnir, a characteristic director Taika Waititi attributed to the handle being made from the arm of the adolescent Groot, and carrying over some of that character's moodiness at that age.
During the Avengers: Infinity War Vudu Viewing Party, one fan asked directors Joe and Anthony Russo if this meant Groot was also "worthy." The Russos clarified that the worthiness enchantment that Odin placed on Mjolnir was specific to that original hammer and does not transfer over to all of Thor's weapon.
Thor. In Thor 1, he is no where near as powerful as he is in Ragnarok or Infinity War, but he is still strong enough to be considered a god by a physically superior race. He can control lightning, and Groot is a tree. He could instantly vaporize Groot, leaving him nothing to grow back from.
After Thor nearly kills himself to build the Stormbreaker axe, Groot gives him his own arm to use as the handle. That helps to bond the two heroes quite quickly as Thor then introduces Groot to Steve Rogers as his new friend – even if he does simply call him "Tree."
Groot entered the battle against the time-traveling Thanos alongside his allies from Wakanda. Groot and the others bought Iron Man enough time to use the Infinity Stones to expel the invading forces, but he lost his life in the process.
Groot's language is known to Thor, but he's likely just calling Groot “tree” by his looks rather than his name. In the comics, Groot's actual full name is “His Divine Majesty King Groot the 23rd, Monarch of Planet X, custodian of the branch worlds, ruler of all the shades.”
It was Smart Hulk's opinion that only he could do it, but it's possible that Thor too could have managed the snap, but perhaps not without suffering even worse side effects.
Unlike Mjølnir, however, the weapon is not enchanted to prevent those deemed "unworthy" from holding it, making anybody with sufficient strength capable of using the weapon.
While the primary Thanos from Earth-616's universe was defeated and was never worthy to lift Mjolnir, it's possible that a future (or existing) variant of Thanos could.
Although Stormbreaker and Mjolnir have very similar properties and powers, Stormbreaker is the most powerful weapon wielded by Thor so far. The obvious reasons are that Stormbreaker is the physically larger weapon out of the two, and not to mention that it is an axe, which could well be more dangerous than a hammer.
Weaknesses. Language Barrier: To most people, Groot appears to only say "I am Groot." This made communication with most people all but completely futile. Maximus the Mad asserted that whenever Groot was saying his trademark "I am Groot!" he had actually been saying any number of things.
Groot is a Flora colossus from Planet X, the capital of the branch worlds. The Flora colossi are tree-like beings whose language is almost impossible to understand due to the stiffness of their larynxes, causing their speech to sound like they are repeating the phrase "I am Groot".
At first, it just seems like Rocket makes up whatever Groot intends with his words, but the truth is that Rocket really understands Groot's strange language. Because Rocket has spent more time with Groot than anyone else, he understands all the nuances of the words and the way Groot says them.
