I tried starting baby sign language with Braysen when he was 5 or 6 months old. We started with the sign for the word "more" and were going to learn other words once he learned that one. We worked on it for months, and he never picked it up for even his first sign. By the time he was 10 months old, I gave up on it.
Two weeks ago he was snacking on some tomatoes while I cooked dinner. When he was done, he looked at me, did the sign for "more" and said the word "more". I haven't showed him the sign in months, which means this little stinker understood what I was doing the entire time, he just chose to not do it. He certainly has a mind of his own! Now I can't get him to stop, so I taught him the signs for "eat" and "milk" also. What's weird is that since he started signing, he has suddenly started talking more than he ever has.