In the beginning yes a little bit, my stuttering increased as I was learning my second language (english). For me problem was pronouncing certain words. In my first language i could basically pronounce words slower and they would still have the same meaning but in english that's not always the case. But since I was learning new language and i was interested I would take more time to find synonyms and to expand my vocabulary (to avoid certain words). Also i learned Japanese and i can say i had better experience (learning it) with it than english because it's spoken as its written and somehow it's ''sharper'' (no silent letters and annoying stuff like in english with many exceptions although pauses make some words problem because they change meaning) Now I'm 24 and I'm completely comfortable with english as i use it everyday especially with studies (electrical engineering) and i would say i don't stutter more than in my first language