My daughter is 19.5 mo and her brother is 3, she is not really talking yet either.
Our ped evaluated her at 15mo and 18mo and said it is normal for second children to talk later. Especially because her brother never stops talking! She makes some sounds and attempts to talk. She has less then 5 word though. We will have her evaluated by EI at 2 if there is no improvement. But she is expressive (hugs, smiles, laughs) she plays, she understands complex things (M go get the bear from the other room and bring it to your brother), she just doesn't have a lot of official "words"
Have you tried baby signs? I started when my daughter was 12mo and not talking. She picked up 12 signs in less then a month and I can teach her a new sign a day now. It has really helped her communicate! (and probably eased everyone's fears a bit) We always say the word with the sign and go over the sounds, so its not like we are using it in place of talking.
My doctor also recommended more face time and reading with her as well as not giving in (she is the baby, a princess to her daddy and brother) if she is not trying to say the word and is just pointing and grunting.That has been harder to get the boys on board with, but basically it's working. Like she knows the signs for more and milk and she usually says mmmmm when she does it. We don;'t give her eiher if she doesn't actually do the sign and attempt the word.
I hope this helps, good luck.