The word for the intentionally incorrect language used in lolcat captions is lolspeak.
Lolcats are image macros—usually photographs of cats with captions written in deliberately distorted English. The style often changes spelling, grammar, and verb forms for comic effect, as in the famous phrase “I can haz cheezburger?” The wording imitates internet slang, baby talk, and a fictional cat voice rather than representing a formal dialect.
Lolcats became a major internet-meme format in the mid-2000s, especially on imageboards and photo-sharing sites. The term “lolcat” combines “LOL,” meaning “laughing out loud,” with “cat.” “Kitty pidgin” is another label sometimes used for the same language play, but lolspeak is the standard answer to this question.
A common mix-up is Newspeak, the controlled language in George Orwell’s Nineteen Eighty-Four. Algospeak instead refers to coded or altered language used online to avoid moderation systems, while DoggoLingo is a broader playful style associated with dogs.