Good advice from everyone so far. Since you have ADHD I think you should have your daughter screened for it too.....often it runs in families and she may be trying to concentrate when she's mouthing words to herself. There's a man at work who talks to himself a bit when he's programming this automed machine, but I understand why he does it - he trying to be super accurate in his concentration and lives depend on his accuracy.

Could be her lack of concentration is affecting her school work - how are her grades? Its also important for her to be on a regular sleep schedule and being on the electronic devices can be tempting to be on late at night. Be careful not to take more of the melatonin - even though its natural it should be taken as prescribed. Hope things get better and you're a good parent for being concerned.