Same, it makes learning languages really hard. For various reasons I speak about 4 languages badly, but only one language well. Whenever I have to speak in one of the other four it ends up as a melange of all four at the same time and it’s a nightmare.
I think different people respond in different ways, and to different doses. I use Ritalin as a general term people understand but the specific ones we use are different variants of the same underlying medicine, depending on our individual needs.
It’s not a miracle drug but it has definitely made a significant difference, taking things from overwhelmingly impossible to merely difficult but manageable.