Re: vocabulary of a 14 month old....
my daughter started out slow too, at 14 mths she was saying only a few words consistantly, mostly baby talk, her paediatrician wasn't concerened though because she had good receptive language skills (responding to speech by listening to you talk, ability to understand and respond to familiar sounds and words) which is an important milestone that comes before expressive language.
EI services work best if your paediatrician gives your child a referral, otherwise on your own its a long tedious process, can be overwhelming because they mostly deal with serious developmental delays linked to Downs, Autism and so on. Your son's ped is the best source of info for you because he/she will take into account your child's development as a whole and address your concerns from a professional point of view.