bit late here but i feel like my perspective is nowhere in the comments: german is my first language and that is where i developed my stutter (at 5 y/o). i started learning english pretty early on and it grew into a safe space, i was able to communicate without stuttering at all! this is a big reason for why i focused on english language, media, books etc., but eventually my stutter appeared in english as well. now it's as bad as in german, and i'm learning spanish atm and immediately had a stutter there. hope this is useful