Always interesting to hear and analyze how non-natives speak the English language. What’s difficult? What do they mess up?
One random observation: the word “clever.” Most fluent English speakers I know don’t use the word “clever” very often, certainly not as a catch-all compliment for intelligence or savviness. If anything, “clever” can have a slightly negative connotation — like sneaky. Yet many folks in Latin America use “clever” very often and in broad contexts.
Second random observation: “this” and “that.” Neither is technically grammatically better than the other, but you can hear it when it doesn’t sound right.