copy of an older, barely legible manuscript?

[Ruby Novacna]

Now I come across these wretched duplications in the lines, which cause me massive headaches because my decoding breaks down like knocked-over porcelain. Lines without these duplications work, with them – they don't.
Then I noticed something very interesting, which leads me to a theory that I want to question here – in my translation attempts, it seems as if there are often several different versions of a small but very similar section of text, and these variations only concern conjunctions and declensions, which are also similar in the variations.  

Are you talking about language A or language B, or are you comfortable in both? 
Are duplicates quite common in both languages?