I use APL as the sole language for my current job. Previous job was also APL. cumulative 4 years, and I'm under 30 yrs old, which is a bit of an oddity.
APLs are really nice, though! I think they scare away newcomers since they look like brainfuck but it's incredible how you can write fairly intricate programs with one-liners. Also can be incredibly fast since array operations are straightforward to vectorize.
I just wish the K language or KDB+ was open sourced. We'd see people from just about every industry drooling over how nice it is.
