Possible values for say-as attributes

Hi,
The SSML 1.0 spec says in the following section 
http://www.w3.org/TR/speech-synthesis/#S3.1.8

that

"SSML only specifies the say-as element, its attributes, and their purpose.
It does not enumerate the possible values for the attributes. The Working
Group expects to produce a separate document that will define standard
values and associated normative behavior for these values."

Is there a separate document already that we can refer to for the values of
say-as attributes? If yes, where can we find that? If not, would these
values be vendor dependent for now?

Thanks,
Roopa