Mandarin is weird, because I don't think it's that hard to speak at a passable level, mostly because the grammar is so simple. Many people are spooked by tones, but I think their importance for simple communication can be a little overstated.

But then, learning to read and write requires enormous additional effort. When I learned in Beijing, I'd spend a couple hours a day working on grammar/speaking/listening - and then like 6 hours a day of rote practice to get familiar with characters.