I think you are expecting a bit much. Or maybe not but I just don't think there should be consequences for not getting it right at this age, i.e. not doing something for her because she doesn't speak properly. She is only 2. There is no rush, she's doing well. And you know what she means anyway. If it were me I would just say the sentence you want her to say when she asks so she hears how she should be speaking but not try and make her say it. E.g. in that situation say 'mummy can I please watch TV' and then answer her itms.