I say it depends on the language. My mother tongue is French but I learned English, Spanish and Brazilian Portuguese. Of the 3 languages i learned, Portuguese is the one I struggle the less with. I think it has to do with the intonations of the language. They allow for more elasticity, the same way singing does. English and Spanish are a little bit more challenging but there are ways to get around it. Remember, when its not your mother tongue, you can always faint that you are looking for a word when you feel a block coming ;) . My advice to you is dont think you will stutter more. You may find it surprisingly better. Plus Ireland is an awesome place so you will have a blast! Boa sorte com tudo! Aproveite esa experiencia!