Why, at 1.5 years old, is it necessary that she be weaned from the bottle ?
yeah, I know, I was more into the accomplishments with my first two children than I was with #'s 3 and 4. But 3 and 4 got the blessing of a busy mom who realized that whether one used a bottle until age 3 just because you "liked it" didn't really matter half so much as having a happy and healthy home. Child #1 became acquainted with the sippy cups that don't spill ?? Well, on her suggestion we tried them, but we found that the younger kids couldn't sip strongly enough to get anything out of them. I tried it once, and it was DIFFICULT. So we pulled the anti-spill mechanism out of the cap, and then it poured out the sippy hole just like an old fashioned sippy cup. And then the kids could use them.
There is nothing sacred about a sippy cup. Your 19 month-old could go right from a bottle to a real cup if you wanted to. When I did that move, I used a glass, that I controlled, because the kids have to learn to use a cup. They tend to try to chew it at first, and a lot of fluid leaks out around the sides until you and the child get coordinated. But it's fun (and can be funny if you treat it right).
Why not offer choices ? We did cups at meal time, and I let the kids have bottles during the day. They didn't spill, it kept the child happy and hydrated, and who was it hurting ? (My mother, who thought I was awful for letting a 3 yr old have a bottle like her baby sibling -- I thought the complaint was WAY more bother than the bottle. And neither child #3 nor #4 went to kindergarten toting a bottle)
But if you really want to get rid of the bottle -- try a sports bottle -- there's no nipple, but it is something you suck. It would make your child appear "older" cuz she/he gave up the nipple ???