There is no general rule. Indeed, the first FAQ says "technically, Int-enhancing items (...) should grant a specific language", not that they actually do. It's basically a suggestion to houserule it because the writers screwed up.
There is no general rule. Indeed, the first FAQ says "technically, Int-enhancing items (...) should grant a specific language", not that they actually do. It's basically a suggestion to houserule it because the writers screwed up.