What does ermahgerd mean and in what language?

"Ermahgerd" is a humorous misspelling of "Oh my god" that's meant to imitate the way someone might speak with a lisp or with a very exaggerated pronunciation. It's considered Internet slang and doesn't have a specific language of origin.

The term gained popularity in the early 2000s, likely due to its use in humorous images and memes, particularly those featuring a cat named "Keyboard Cat".