How do languages work now if they are not skills in the old sense?
. Languages are advantages. They work by letting you speak/read/write. Usually, you don’t roll for this, but if your comprehension isn’t perfect, you’ll have to roll vs. IQ or a skill — at a modifier — to communicate with others. Thus, having a language is largely qualitative — you do or you don’t, although there are levels of this. Using a language depends on your smarts or training.
