I’m a Bengali who stutters as well, English is also my first language. I would say it’s almost evenly split for me - I stutter in both English, Bangla and the Qur’anic Arabic that I recite during prayer, duas and reading the Qur’an. The qaf “ق” letter is one the hardest to get through for me 😅 I definitely feel like I can mask my stutter more with English