Korean is with a few exceptions. Hindi has male and female but only denoted through verb endings. Japanese has no grammatical gender iirc but makes a lot of social distinctions between male and female.
Of these three, I guess Hindi is the easiest to learn. Simple alphabet, two tenses, no special characters to know. I guess Korean is a close second. But all of them I'd consider easier to learn than English.
I think English has two advantages : 1- it is already very widely used 2- more importantly, it is a fairly simple language compared to French , German , Arabic , Mandarin etc. Can't really think of a language simpler than English
