You need a unicode-enabled browser with japanese fonts installed to see the Japanese in this write-up.
Japanese is romanised as Hepburn. Kanji entry would be impossible without tongpoo's Unicode converter
Gai-on (外音) are a new development in written Japanese that has only appeared in the past fifteen years or so. It is kanji
that is used to represent a borrowed foreign word (almost inevitably English). Perhaps this can be considered a logical extension of the way that kanji has always been used by the Japanese, but it does not fit into the traditional schemes of kun-yomi
An example is 高技: the reading you would expect is either kōgi (on-yomi) or takawaza (kun-yomi). The actual reading is hai-teku...or 'high-tech'!