The language in the notifications a user receives is the same regardless of whether they are a signer or a cc'ed recipient. There is no call to action to sign the document, so they cannot tell if they need to take action or not. I'd like to have a signer receive a message to "please sign the document" or "your signature is required" or something, whereas a cc'ed recipient should receive a message like "you've been cc'ed on a document."