Depends on what the code is doing! Typically I “see” the underlying concepts or data structures interacting with each other. Imagine those block and arrow diagrams you would have in a textbook explaining how pointers work, except it’s completely automatic for me. My day to day involves a lot of low level systems stuff, so reading a page of code could spawn an image of how various event loops, memory allocations, etc. interact. Then to explain what I’m thinking of to a colleague is sort of like describing what I’m already “seeing” in my mind’s eye. Language to me is just an interface to this inner visual world.