Ascendis Caller ID can speak the names of callers or arbitrary text if you have Microsoft's Text-to-Speech engine installed.  The speech engine is include with Windows XP and later.

Speech is supported through actions. Easy actions provide a checkbox for "Speak" and a place to put the text to speak. Advanced actions can use the "Speak" command.  Either method can use macros to refer to caller information.

You can change the voice used and the speech rate on the Speech page of the Options window.