Hi, Getting stuck when speaking another language usually means being at a loss for words. So you may look the missing word up in a dictionary or work around the problem. Getting stuck in your own language could be a very different thing, and might be due to stage fright, or just being surprised by a question.

I keep getting stuck when I speak Russian, and I also often get stuck when I speak Spanish. It's a perfectly normal phrase. Stuck = fixed, like when paper is fixed or affixed with glue/adhesive. Pipes get blocked, and mechanical things get stuck - they don't move because there is a problem; it's jammed, it's stuck.

Movement ceases, progress ceases, . I am stuck for the right word. I am stuck right now, I cannot get past these phrasal verbs based on "up". Whenever I speak to foreigners, I always find myself stuck for things to say that I have the vocab for. Whenever I speak to foreigners, I always find myself stuck for how to say things. My mind just goes blank.

getting stuck based on wordreference means "unable to moove, to proceed" in your context that can be you became shy ou you lost all your ability when it is about english

Getting stuck = stopping to think