On Windows, text-to-speech is easy. Windows has a builtin text-to-speech service. Even Windows XP has it.

If you save the following code as a text file and rename it to SPEAK.VBS and then call it from Perl...your Windows PC will speak! The first argument should be a number between 1 and 100. The second argument should be some English words enclosed with double quotes. (If you omit the double quotes, then it will only read the first word.)

IF Wscript.Arguments.length > 1 THEN
    SET VOICE = CreateObject("SAPI.SpVoice")
    VOICE.Volume = Wscript.Arguments(0)
    VOICE.Speak Wscript.Arguments(1)
    WScript.Quit 1
ELSE
    WScript.Echo "Usage: speak.vbs <VOLUME> <TEXT>"
END IF
WScript.Quit 0
[download]

(Note: Don't send too much text all at one time, because the computer will freeze up while it speaks. At least, that's what happens in Windows XP. So, if you have a bunch of things you want the computer to read, then call SPEAK.VBS with just a few words at a time. That way if you want to press CTRL+BREAK, you can interrupt your program, and it will stop speaking. But if you call SPEAK.VBS with a whole paragraph, it will not stop until it has finished reading the entire paragraph.)