In late 1999 DC Comics produced a unique Superman merchandise item... a Green Kryptonite prop. On the outside of the box the Kryptonite came in, was the following English/Kryptonian Transliteration Guide.
English/Kryptonian Transliteration Guide
Please note that transliteration is approximate.
Some variance from actual Kryptonian pronunciation is to be expected.
You can download this font for use on your computer.
An unofficial Kryptonian language page
has been set up by Darren Doyle, a linguistics university student who took up the challenge to create a fully-functional Kryptonian language. It has to be seen to be believed. The website also contains a complete guide to the Kryptonian language created for the "Man of Steel" movie in 2013.