At some point in their adult life, most people look back on the years they spent in high school language class and feel a particular kind of quiet regret. They studied Spanish, or French, or German, for two or three or four years. They conjugated verbs. They memorized vocabulary lists. They passed the tests. And then, outside the classroom, they found that they couldn’t actually speak the language — couldn’t follow a native speaker at normal speed, couldn’t find the right word when they needed it, couldn’t hear the language as anything other than a stream of sounds that had to be decoded one word at a time.