Try clicking these links:
http://www.mamasource.com/request/recent/96824/1226611244/19
http://www.mamasource.com/request/12028098121742417921
http://www.mamasource.com/request/7220631653587091457
This question is asked from time to time on Mamasource.
If anything, you can have your daughter assessed. Here where I live, thru the Easter Seals organization, they have a "Zero to Three" program whereby they offer FREE services for any developmental concerns, for any child up until 3 years old.
Each state seems to have a "regional center" from which these services are offered. Ask your Pediatrician, and they should know EXACTLY where to go and who to call. For these services, at least in my State... they even come to your home for it. So it is REALLY great and convenient.
My son, receives Speech Therapy through this program here in my State. It's free. My son is just a late talker... he is 27 months old, and he was assessed, and their is NOTHING wrong with him clinically or with his development. My son is also "advanced" in many areas, but he just does not want to talk...but plus he is bi-lingual... so he uses both languages. But I have the speech therapy for him because is it free and it is helpful.
Speech ability has nothing to do with "intelligence." My son, has enormous understanding of whatever we say or ask of him, in BOTH languages. He was this way from even before he was 1 years old. BUT, he is just delayed in speech. Its not big deal. Einstein didn't even talk until he was 3 years old. And many other historical "geniuses" were this way as well.
BUT, it is good to have the child assessed... just to get a "picture" of how you can help them, and to ease your worry.
DO NOT feel pressure from your family. DO NOT get self conscious... but early intervention and getting an assessment is useful... my son was assessed at 19 months old. He has, on his own and from my "learning" techniques from the Speech Therapist... become much more talkative.
You will also be having another baby soon... and this means your daughter will have more to adjust too. I hope she is "ready" for all that it will change in her life. A child this young... NEEDS help in the transition. PLUS, she is almost 2 years old... and this "age-stage" is full of growing-pains and changes for the child... just be ready for that. :) She will have a lot on her plate to contend with...plus her Mommy will be busier with baby. *And I say this with much empathy... but DO NOT PRESSURE your eldest daughter to "be" a certain way or to "be" perfect, or to have high expectations put upon her once the baby comes... this will often backfire and just cause stress & regression in a child. Let her be... let her be a child. This is more for your family to be aware of...since they seem to pressure about just her speaking ability.
Anyway, sorry for rambling and getting off subject.
Don't worry... but early intervention is good and helpful, even if there is nothing wrong... which is probably the case.
Some kids just won't talk until they are ready... but, you want to make sure their mouth/muscle/tongue coordination is fine too... which is why some kids don't "talk." AND.... at this young an age... THEY DO NOT HAVE TO SPEAK PERFECTLY. It DOES NOT matter if she does not say words "clearly" or correctly... she is only 21 months old. This is per our Speech Therapist... so tell THAT to your family. This is NORMAL.
All the best,
Susan