prefix and suffix in indonesian

(It is not my second lesson indonesian note, but just another note)

awalan ke- dan akhiran -an
(prefix ke- and suffix -an)

i will explain these by english viewpoint not indonesian, so it is easy to learn.

when we see at these group of words:
strong, weak, still, pure

when translated to indonesian:
kuat, lemah, tenang, murni.

let's see group of words below where have been modified:
strength, weakness, stillness, purity.

if we want to translate those to indonesian, just give "ke" at thebeginning and "an" at the end like below:
kekuatan, kelemahan, ketenangan, kemurnian.

may be my english is messy but I hope you got the point.