FWIW, I did a diff of [one version of] the Hebrew: http://blog.purepistos.net/psalm-14-53-hebrew-diff.html

I took the text from here:

http://www.ancient-hebrew.org/hebrewbible/Psalms_14.html http://www.ancient-hebrew.org/hebrewbible/Psalms_53.html

and split it (more or less) into one word per line.

You'll notice that, in some cases, even when lines or sections are technically different (characters do not exactly match), there is a similarity of words (same roots).