I don't think I've said on this instance how good I think the Open Logic Project is.
@twsh I've said for a while that I'd love to teach Lojban as an intro to logic course for undergrads sometime :)
The Complete Lojban Language (CLL) is also free and would make a great text
@bgcarlisle You could presumably get in to philosophy of language and linguistics quite quickly too.
@twsh All I'm missing is a tenure track professorship in a philosophy department