As a Polish speaker I communicate with Claude using my native language and it does the same things. Most annoying and slowing down things are:

- acronyms and shortcuts - it makes it's own and start using it without introduction

- exotic names of variables or functions - it uses them as examples or analogies, but when I ask what they mean and where are they from it gives me answer that it came from C language or some C library (I only work with typescript and python)

- convoluted descriptions of code behaviour - it's hard to rely on a outcome of prompt of type "explain code in..."