Lots of reasons. First a lot of us native English speakers are monolingual, because that's all we need to be. A lot of us view fluency in another language as s

Lots of reasons. First a lot of us native English speakers are monolingual, because that's all we need to be. A lot of us view fluency in another language as something reserved for incredibly intelligent people. Esperanto is so easy to learn that it disabuses us of that notion. Secondly, linguistic curiosity. What's a constructed language designed to be easy to use actually like? Is it as easy as people say it is? Lastly, community. There aren't as many esperanto speakers as there are Hindi or Spanish or Mandarin speakers, sure. No one is denying that. But a brief search suggests there's 100,000 active speakers, which isn't nothing.