Esperanto was the first language I've made any real progress with. Spanish is considered a fairly easy language for English speakers to learn, but I knew fairly little after 3 years of study in school. I've put in substantially less Esperanto effort, but am far more confident. I actually believe I could become fluent if I continued to focus on it. When someone (even with an accent) speaks, I can understand the sounds and spell the words no problem. It isn't perfect, but I find learning it fun and not frustrating. The community is also vibrant.