my son had a significant speech delay. As a baby he drooled more than most and could not lick pudding off the sides of his mouth. even during babbling speech therapist noted insufficiencieis.
What concerned me was that he never bounced. You know when you hold a baby up and they push up with their legs and bounce? Erik never did this. Erik's speech was not delayed at all. I think his 3rd word was combine (we live on a farm).
Just my 2 cents, my step-son Brandon was a late walker according to his mom and dad. I believe they said he was about 18 months when he finally started walking. His dad said that he actually didnt talk much up until he was about 3. He had his adenoids taken out when he was 3 and my husband says they couldnt get him to be quiet after that! He still has some speech issues, but they are mild. Most folks dont even notice them. He has trouble at times with "finding" the right words. Once he "finds them" though, he is on a roll! His dad says he cant remember if Brandon had the drooling.