as regards the pronounciation - does the X in Greek sound closer to "kh" as in sakhar (russian) or khuda (persian) ; or does it sound more like H as in hungry or hell ? Also do the Greek phonetics carry a universality through all its dialects ?
It is a "breathed" k sound (not an h). Many native english speakers can't hear the difference, and it is commonly pronounced simply as a hard "K" sound. There are (not including rho) three "breathed" letters: theta, chi, and phi. Generally, these are now pronounced "th" as in "then" or "thin," a hard K, and f. However, it is likely that the actual sounds were: theta= th in outhouse, phi=ph as in uphill, ect.