I just saw this thread and had to open in because my first thought was - Does Astrid know my DD???

Then I read the OP and I swear I could have written every word myself. My DD is exactly the same. It is so tiring and so frustrating. The worst for me is that I work during the day and DH stays home with her, and whenever they go out, he usually gives in to her just to stop the whingeing (little realising that giving to her will only stop for 5 minutes until she wants the next thing...).

Not sure of practical advice - what I am trying to do is:
1) Compromise with her - e.g. if you get an ice-cream then we can't look at toys - so which would you prefer?
2) Tell her I'm not listening until she starts using a normal voice and tone. Good idea whoever says "I can't understand you". I must try that.
3) Explain to her that people can't get what they want all the time and sometimes explain something that I would like but can't have, e.g. "mummy would like to buy those shoes, but we don't have enough money for them", etc.