How to improve verbal/written skills in the workplace?

Hello everyone, I am currently working at a company where most of my colleagues are Americans. I am from a country where English wasn't my first language, and I think I need to improve my verbal and written communication skills. I tend to make direct translations of my ideas but I have noticed my colleagues have a nice and polite way of framing sentences. eg. If there is something I don't know, I would just say it as "I don't know how this works" vs others who would say it as "I am not quite sure how this works". There are many other instances where I see this pattern, and it concerns me that I might be coming off as rude. Does anyone have any suggestions for books/videos that would help me learn more about American workplace communication skills? Thank you.