Learning to Talk

Brianna has a good list of words she can say. She started talking before her first birthday by saying "dog" or "oof". I have come to the conclusion that we will probably always have a dog since she seems to love Lady so much. Her favorite thing to do now is to tell Lady to "sit" although it often sounds like she is saying something else that a young lady should never say! She won my heart the other day by saying "shoes," I have a girly girl on my hands (at least for now)! Hopefully she will like shopping and doing other girly things as well! She likes to say "hiie" to everyone. It is so cute how she draws it out and emphasizes the "e." "Dad-dee" is her favorite person (besides maybe Owen). The other day he was outside and walked past the window and she called out to him. I guess she sees me so much that she doesn't think she needs to know my name. We walk downstairs in the morning and she is already saying "kiddy-cat." Again, I think we are stuck with indoor animals for quite awhile.
The only things she seems not to say is more, drink, up and other words along those lines. My sister-in-law seems to think I should start making her ask for her drink and such. I don't know. When I try this she screams and cries. She ends up so upset that it takes her quite awhile to calm down. I know she needs to learn, but at what age do you make them ask you for things? I don't want a spoiled baby that grunts and points for everything, but if she is not at the age where she should be asking for things then I don't want to push it. I tried looking this up online and in some books but found nothing that really said anything about this topic. She goes to the doctor for her 15 month check-up in a few weeks so I guess I will ask him.