[lojban] Language vs. tongue? (was: native language)

[jexOm. <lojban-out@lojban.org>]

Hello,
A little off-topic, but it is a question I always have when reading 
articles about linguistics in English. What is the difference between a 
"language" and a "tongue"? Is lojban a language or a tongue? To me, 
it's a tongue, but I very often read "language" instead. To me, a 
language is more a whole category of communication means (like signs, 
music, etc).
Thanks,
  Jérôme.