Hi there,
I totally know where you're coming from since I've been there w/ my son. My son started walking around 16 mos and only had a 5-10 wrd vocabulary by 2 yrs. His pediatrician said at 2 he shld be putting wrds together and told me he was delayed. She suggested early intervention. From there, my son went into a special ed. pre-k where he got speech therapy, OT and PT. He is now almost 5 and is doing a lot better. I wld suggest talking to your child's pediatrician. Some drs. are more layed back than others. Also, for your own peace of mind, have your child evaluated by a developmental pediatrician through your local hospital. Since you said this runs in both sides of your family, I wldn't wait. The earlier you get your child help, the better the outcome. This may just be a delay, or it cld be something else. I understand how this can be both frustrating for you and your child, but there is help out there. Please write if you have any further questions. Good luck!