Hi Jenn,
I'm a home child care provider myself. One of the kids I watch is 17 months and as far as his vocabulary it is a little slow. I tell them what color things are and we try saying different words, we go over what everyones name is.
Now on the flip side of this I also watch a little girl that will be 1 in a week and she can uh oh.
I also watch a little boy who is going to be 1 at the end of Janurary and he is starting to say words like Hi and uh oh.
I also have a 1 year old myself. She is 14 months and she says Uh oh, Dad, Mom, Bud (our dogs name) and Alex one of the little boys I watch. The point I'm trying to make in on this is that even with my best intentions they will still talk and develop in their own time. Not just what I do but it's a team effort with the parent and provider.
For your own child you need to make sure on your end that you are making her communicate with you on things she needs and wants and not just grunting or making noises. After that you need to talk to her teachers at daycare find out if she is communicating with them or trying to. And in this communication between you and the daycare will go along way. If you aren't talking to them about your daughter not commuicating but she is communicating with them at daycare how are they gonna know what issues you are having if you are not talking to them on a regular basis.
I have a 3 year old daughter also and I watch a 2 1/2 year old, we do learning time for 2 hours a day everyday and so far they know all of their letters but 5 and can count from 1-10 and they know all of their shapes and colors. Now why are they doing this well you ask ? Well thats because for the little girl that I watch her parents go over with her what we have done during the day. Everyday we work on letters, numbers, colors, counting, writing, shapes and identifing the letters upper and lowercase. It is a team effort between us.
I also don't think it would be a good idea to let Grandma watch not for the concern of whether she would take care of her or not but because theres alot of things your daughter gets from being with other children.
For good example my 2nd child was watched by his Grandma and she loved him and took really good care of him but where he lacked at was social interaction and communication skills and speech. I started staying home with him right before he turned 3. When I started staying home with him I couldn't understand a word he said but after alot of hard work and a year later and me starting my own daycare it all came together and now he talks great. Your daughter may be on the slower end of talking but you may see that after awhile she will just start talking up a storm.
So my advice talk to your daycare provider see what is going on there, voice your concerns before you jump the gun. Let them know she isn't talking much at home ask them how she communicates with them. Ask them if they are encouraging her to talk and communicate and not just with them but with kids in her class.
Hope this helps, W.