Our dd barely hit the speaking milestone (6 words) at her 18 month check up with the pediatrician. 7-8 months later she was both speaking and reading well. She was obsessed with reading (then and now), and I believe reading helped her learn to speak. (To this day, now 12yo, she makes pronunciation errors due to a huge vocabulary learned from reading.) At the time she was a toddler, there was some fanfare in the press about hyperlexia, and we did consider for a while that her reading could be a sign of that rather than giftedness.
We thought her twin brother ("the control sample") was not gifted because he didn't learn to read until he was 3.5 yo. But it turned out he is too! -- I guessed we figured that out early in elementary school.
