My year and a half old son is very social and a babbler, but only has about 6 words that he'll say consistently. About 2 months ago, he was showing a lot of progress, and added about 10 words to his vocabulary, although he'd mostly say those with prompting. Then, we moved from DC to Florida, and he pretty much lost those 10 words. He continues to babble a lot and will sometimes (rarely) repeat familiar words. Anyone know what's normal for this age? Should I schedule a follow- up with his pediatrician before his 2 year appointment?