OH please do not make your daughter write sentences. I used to have to do that, and it just frustrated me - it never stopped me from talking.
I'm very outgoing and used to get into trouble for talking in class ALL THE TIME.
I would just sit down w/ your daughter one on one and let her know that you know she likes to talk to her friends a lot in school, but explain to her that it is disrespectful to the teacher (ie only one person talks at a time), and to the other children who are trying to learn. I think its most important that she knows WHY she shouldn't do it - not that its just 'not allowed.'
