The question didn't define "fluently" as "never needing to look anything up." I think the concept of fluency (of any kind of language) is being able to use it w

The question didn't define "fluently" as "never needing to look anything up." I think the concept of fluency (of any kind of language) is being able to use it without significant effort. e.g. I would consider myself "fluent" in Java, but not Lua - that doesn't mean when I write Java I never have to look anything up, but certainly far less so than hypothetically writing the same thing in Lua.