Iron Man is one of the main characters in the Marvel Cinematic Universe and had its own movies before the big franchise started crossovers like The Avengers. With his attitude, he became the favorite Superhero of a lot of fans. Not only that caused a lot of screen time for Robert Downey Jr.’s Tony Stark, but it looks like that extends to dialogue as well.
A Reddit user recently analyzed the MCU’s Avengers-related movies and that proves that Tony Stark is the one character that talks the most in the analyzed movies: The Avengers, Avengers: Age of Ultron, Captain America: Civil War and Avengers: Infinity War. It was clear that for example Bruce Banner, Thor or Hawkeye had no chance to compete with him in the first place. They don’t even show up in every of these movies. Iron Man does but Stark’s contribution of lines and talking is stronger than Captain America and Black Widow.
Captain America aka Steve Rogers is our runner-up and Black Widow following, except for in Avengers: Infinity War, when Thor seems to talk more than usual for the God of Thunder. For Tony Stark, however, it is clear he is the “King of Words”.
As @reddit_user_1948 explains, the data was compiled by keeping track of “each time a character speaks,”. They also counted one exchange as two separate lines in certain instances, such as “if one character speaks then something happens for a few moments and then he/she speaks again.”
This isn’t offical data but representive. Tony Stark is an important character for sure, but especially in Captain America: Civil War it is remarkable that Stark talks more than the man this movie is named after, Captain America. The character of Tony Stark/Iron Man is very complex and “started as a very narcissistic, self-centered character,” as Anthony Russo said. There has been a lot of progress to the character and also showed that even superheroes can be emotionally and metally stressed and harmed by the things they experienced.
We don’t know if Tony Stark will be one of the characters with the most lines again when Avengers 4 hits theaters on May 3rd, 2019. A lot of fans expect Stark to be in the center of the ongoing MCU story and in the fight against Thanos. So it would makes sense, but we will see.