I also read that a lot of the movie was improvised. When the actors brought that up to David O Russell saying it would alter the plot his response was "I hate plots. I'm all about characters. That's it"
......annnnd that pretty much sums up the movie
Jennifer Lawrence says her character channelled the women on the House wives of New Jersey tv show. Said the show is her guilty pleasure when she's not working and watches every episode religiously. She copied their accents and manurisms,etc to play the part.