The speak-as descriptor specifies how a counter symbol constructed with a given @counter-style will be represented in the spoken form. For example, an author can specify a counter symbol to be either spoken as its numerical value or just represented with an audio cue.
If the value of speak-as is specified as auto, then the effective value of speak-as will be determined based on the value of the system descriptor. If the value of system is alphabetic, then the effective value of speak-as will be spell-out. If system is cyclic, the effective value of speak-as will be bullets. If system is extends, the value of speak-as will be the same as if speak-as: auto is specified on the extended style. For all other cases, the specifying auto has the same effect as specifying speak-as: numbers.
A phrase or an audio cue defined by the user agent for representing an unordered list item will be read out.
The numerical value of the counter will be read out in the document language.
The user agent will generate a counter value as normal and read it out as a word in the document language.
The user agent will generate a counter representation as normal and would read it out letter by letter. If the user agent doesn't know how to read out a partiular counter symbol, the user agent might read it out as if the value of speak-as was numbers.
If the name of another counter style is specified, the counter will be spoken out in the form specified in that counter style, kind of like specifying the fallback descriptor. If the specified style does not exist, speak-as descriptor assumes the value auto.