Interesting. Try highlighting "tune" and "and" and it will give you three different pronunciations for each, but it is still the one guy's voice (didn't sound robotic to me, just seemed like a slight British accent (to an American)). The volume oscillated up and down when I highlighted several words at a time.
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I prefer
forvo's approach, you can get a human to pronounce it for you, add your own words, record pronunciations yourself using a builtin Flash applet, and hear native speakers from several different countries or regions.
Plus it's not English only. You can also use your favorite browser search addons to look up highlighted text in Forvo just like any search engine. I have no affilation with them other than being a user (yes, I am kind of derelict in my pronouncing duties, I have only pronounced one word there so far).

And if anyone knows Punjabi, go here and pronounce
ainvayi for me, thanks.