(funny thing, Windows also has a similar solution lately -- at least on Windows 7)
The inclusion of text-to-speech in operating systems has not been voluntary on behalf of OS vendors. It has been driven by lawsuits from disability campaigners, particularly for blind/ impaired vision people. It's also why they've introduced things like high-contrast display modes display magnifiers etc.
I don't know
, but I strongly
suspect that soe of those lawsuits have produced lists of desired features, and the commercial OS vendors have put those lists to the code slaves for implementation. So it's no great surprise that it looks as if they're singing from the same hymn sheet, because they, ummm, are singing from the same hymn sheet.
This definitely isn't an area I claim any expertise in, but Linux users aren't left out in the cold. Anyone who has used the stupendously useful Knoppix CD/ DVD/ USB rescue system
will probably have noticed that Klaus includes a text-to-speech engine called
A.D.R.I.A.N.E. (Audio Desktop Reference Implementation And Networking Environment) is a talking menu system, which is supposed to make work and internet access easier for computer beginners, even if they have no sight contact to the computers monitor. A graphical environment with also talking programs and arbitrary magnification using compiz, is another option.
I can't give any citation of how good this is, but I can assert that the rest of the system is a phenomenal piece of work, and it's a pretty safe bet that Klaus has done a wonderful job here too.