I have 5 kids and they are/were all different. The earliest for me was 6 months for first words. He said: ball, bike, baba, baby, binky and mama all in one week at 6 1/2 months old. By 12 months he was speaking in complete sentences.
On the other end I had a delayed child who didn't say her first word (mama) until she was 16 months, only knew 2 words (mama and dada) at 18 months and didn't really start talking in sentences until she was almost 3 and then it was hard to understand her. They are 9 and 8 (respectively now) and you can't tell the difference between them with their speech (except the previously delayed child NEVER stops talking now, lol).
My youngest is about to turn 1 (next week) and hasn't said a definite first word. He babbles mama, dada and, occasionally, baba but none of them consistently.
at 11:33 AM on Jul. 6, 2011