D.T.
To reiterate what many mommas have already said it varies between children but I think my ped said there should be a minimum of 30 words by age 2. I had read in many books that there should be up to 200 words by that age but doctors only trying to find the worst case situations, not those that may be on the slower end of developing (which isn't a bad thing). Although both grandchildren may be 2 years old a few month difference can be huge in terms of speech development. At one time my nanny's 25 month old daughter seemed to know about 25 times as many words as my 22 month old and I was concerned, but by the time he was 25-26 months he was on track with her at that age.
I know that friends with children with chronic ear infections have had some speech development issues so the can be an indicating factor. Good luck.