What would be an appropriate punnishment for a very frustrated child ?

[mummyloveslucy]

My 3.5 year old daughter has a speech disorder and is becomming increasingly frustrated with herself (as she knows she can't make the words sound right) and with me for not always understanding her. She looks to me to translate all the time when she's talking to people, but when I don't understand she gets VERY upset.
She has started shouting "look at me, look at me" while pulling my face close to hers then when she says it again and I don't understand she smacks me.
This has only happened twice when she's been extreamly frustrated. I punnished her by saying in a very calm but firm voice "I know it's hard for you, but you do NOT smack mummy". I then put her in her room for 3 mins time out. When I hear her crying in there, I feel soo bad. It must be awful for her but I don't want her to think that it's o.k to smack. I have never smacked her in her life and don't intend to, so I don't know where she's learnt it.
Am I right to put her in time out? or should I deal with it differently? She dosn't mean to be naughty, she just gets desparate I think. She is a very loving little girl but somtimes I just feel useles.

re the drawing/scribbling. You could always ask her to scribble how she feels when she's cross. If you think she's going to hit you give her the paper and ask her to draw how she feels then look at it and say stuff like. "Wow those are really angry scribbles, you must be so cross." It shows her there are other ways to express her anger and that you understand. Or maybe give her a special cushion to hit when she feels no one understands her?

I think the baby signing is a really good idea. You can make up signs for favourite people and places as long as you are consistent you don't have to use an existing system although she will be able to be understood by a wider range of people if you use makaton or BSL. The other benefit with signing is that it uses new areas of the brain to help with remembering words/sounds so it might help with her language development.