To some other ones. It doesn't have three alphabets, but in general I've only ever been told it is horrible to learn. Too many words that mean too many things, and too many variations depending on geography. A lot of it is easy to work out (colour), but learning Side walk and Pavement for the same thing because two different versions call it two different things is confusing.
Dialects and geographical differences exist in different languages, too. I'm german and there are at least two german dialects I couldn't even hold conversations with. There are no gramatical cases and stuff like that in english. Where english just uses "it", other languages still differentiante into male, female or neutral nouns. Verbs have different forms depending on the pronoun.
There's quite a bit of stuff like that.
Most of those languages tend to make sense when your pronouncing them though. English words just has whatever letters it felt like slapped onto them, and no one bothered regulating that the sounds were generally consistent. (deer, dear vs beer bear).
I'm not saying English is the hardest language in the world, but if we're speaking relative to Korean, it shares few enough similarities that I don't think it's all that simple for them.