Thieves Cant and Druidic are one thing, but I always thought that alignment languages were problematic. An alignment would be a very personal thing. How do you know that it's 'safe' to use your alignment language with someone? Around others, in general? You're potentially revealing an awful lot about yourself, whether or not the other person can understand what you're saying. Just because I don't understand Russian, that doesn't mean that I don't recognize that you are, in fact, speaking Russian.