> where does that statement 'horrible to learn' come from?
I had French, English, German, and Dutch in school. I'm a native Dutch speaker. English was easier than any other language. I'm pretty sure my English grammar is better than my Dutch right now. I mostly understand the d/t rules in Dutch by now, but I'm not always certain. French, German, and Dutch classes kept introducing lots of random rules that serve no purpose. At the end of high school, the only language I could hold a grammatically correct conversation in was English and my native language, and write a grammatically correct text only in English (not Dutch, or at least not without avoiding certain rules by rewriting sentences).
English classes also introduced some silly random rules at first, but once you get beyond the a/an, learn a hundred or so irregular verbs, and a few other such things, you're mostly done and it's just vocabulary and expressions/sayings left. You can't really get around the latter, but the former can be kept as small as possible (only the useful features like indicating possessiveness or plurals, not differentiating between whether the object you're speaking about is {male, female, neuter} × {active, idle, giving, modifier}). And the German sentence structure is more convoluted than necessary (I forgot most of my French, maybe theirs too), plac[1] the second part of a split verb so far at the end of the sentence with lots of words and qualifications in between that you lost track of what came before when you finally reach the end of the sentence especially if you can't really read German fluently [1]ing, but maybe that just takes some getting used to.