Originally posted by AdrianN ps. why do Americans pronounce Nikon as nai-kon?
Because the vowel "i" is pronounced as "ai" in a lot of words that begin with Ni. Night and nice, for example. Even the pronunciation of "i" in words like "nickle" is more of a "neh" sound rather than the "knee" sound of pronunciation of に/い. Also, the vowel length is often times dynamic, so if you extended the length of the "i" to a "knee" sound, the "o" in the "kon" would probably be shortened. Then we'd probably end up saying Kneecon, with the con being pronounced like beacon.
Either that or we just don't watch enough Monty Python.
P.S. It's always funny how much people nitpick Americans on the pronunciation of Japanese words when they positively butcher English. マクド (Makudo, McDonalds), and スタバー (sutabaa, Starbucks) come to mind.
P.S.S. There's also no X sound in Japanese, so technically we should all be saying Pentakusu.