I definitely stutter more in my native language than in English. I don't know why. Interestingly enough, since for the last 2 years I've been speaking mostly in English and all my daily interactions are in English now (I don't live in my home country anymore and I only know like 3 people here who speak my language, so it's safe to say I speak Spanish like maybe once a week or less?) my stutter in English has been getting progressively worse :)