That's Fun to Say

Sam was playing in the living room while I was cleaning up the kitchen and he just kept repeating the word "limestone."

Sam:  Limestone.  Limestone.  Limestone.
Me:  Why do you keep saying that?
Sam:  Limestone.  It's a type of rock!
Me:  Yes, I'm aware.  But I'm asking why you keep repeating it.
Sam:  Oh.  I didn't know you would know that Mama!  Limestone.  Limestone.  Limestone.  Limestone.
Me:  Sam.  Why do you keep repeating the word "limestone?"
Sam:  Because it's super fun to say.  Liiiiimestone!

I fear he has gone full Buddy the Elf.