Although the story is nothing particularly special, this film's strength is in it's dialogue coupled with outstanding performances by Lewis, Ribisi and Keaton. I have to say that Lewis's portrayal of Carla did take some getting used to, and although it was very good, I found Ribisi's performance to be even better as the mentally challenged Danny; comparable to Leonardo DiCaprio in What's Eating Gilbert Grape.
Keaton's portrayal of Carla's mother is absolutely top-notch. This is a woman who is so stuck in her conservative attitudes that she can't see past the end of her nose. At times she seems to recognise that she is being unreasonable but just can't help herself. She doesn't seem to see anyone outside herself for what they are, she just sees them how she wants them to be, and if they don't fit her expectations and she can't make them change, she resorts to denial. For someone with so much money and social standing she's a pretty miserable human being.
Carla's father is played by Tom Skerritt, and although this is a smaller part he steals nearly every scene he's in. He is quite the opposite of Carla's mother, far more supportive and ready to trust her, but at the same time worried that maybe his wife will turn out to be right after all.
Carla herself has a childlike innocence which makes her very vulnerable and it's understandable that her family is concerned for her safety and worried that she might be taken advantage of by the unscrupulous. Although she is a capable adult, her innocence and lack of social skills causes her to embarrass her family at social functions on more than one occasion. It is however interesting to note that Carla herself is quite happy with herself despite all this, it's only other people's expectations of her that cause her unhappiness. Unlike her mother, she doesn't care about the so-called important things in life such as money, status and career; love is all that matters to her, and quite frankly I agree with her.
The Other Sister was directed by Garry Marshall who was also responsible for Beaches, Pretty Woman and Frankie and Johnnie, and like those films it has a tendency to pull on the heart strings, especially towards the end. If you are not into having your emotions messed with, you'd better stay at home, otherwise I highly recommend that you see this film and let Carla and Danny's pure innocence into your heart too.