How to sound unlike a native speaker

Here's an interesting question asked of native speakers in our forum recently: Other than the accent, what are the most common things that tip you off that the person is not a native speaker? So far, answers have included improper verb tenses, literal translation of English idioms, and mixing up ser and estar. Here's another comment: "Even at advanced levels some second-language learners sound like voices from a textbook or from a tape recorder. ... I can remember lots of times when students use a word right out of the dictionary to talk about simple day-to-day items like belt loops, shower caps, etc., and they just sound plain weird." Join the discussion...