@exim: X followed by a vowel is pronounced using a Z. Xerxes is pronounced Zerxes. Xanadu is pronounced Zanadu. Xamarin is pronounced Zamarin. And if XOR was a real word in the language, then yes, it would be pronounced Zor. :)
@issam: Can you provide more details on this bug? Has it already been reported to us? Is it something that you are experiencing? Feel free to email me at rogreen at microsoft dot com with additional information.