It takes a lot of trial and error, and spending time with her would help :) Even if you don't know exactly what she's saying, you can roughly estimate from the situation and say "Are you ___ because ____?" - she could then respond via body language or more babbling, sometimes it's the random talking to them that helps build the bond!
Usually only the mother will understand but after a few times. initially u won't, but slowly u will be able to understand what your child is babbling!
i have heard people tell me too. frankly I do understand bits and pieces of what my son says but not everything.
it's ok. I also don't understand what my LO is babbling about.
sometime baby language hard to understand.. It takes time