We also never talked to our DS6 in "baby talk" when he was younger...I don't know why...I guess it just seemed silly to us? When he asked us questions, we would answer him truthfully and if we didn't know the answer (even when he was 1-2) we would go to the computer or library together and look up the answer. Friends were always in shock at the questions he came up with and even more shocked when they heard me answer them with "real" answers.