These runes can be written in any language you speak. There is no set one. If you are confused about why there is a: NG, GH, EA, AE, OE, TH they are used like any other letters except that runic symbol takes the place of 2 letters. so in the case of writing "that" it would only be 3 runic symbols long, instead of four.
These Runes were used in the olden days as a "secret language" so it wasn't easily read. There are many different types although these seem to be the most popular. They are still used for writing in Book of Shadows', the writing in spells and I'm sure there many other uses also.