title_body: Software to create bilingual ebooks? Suppose that I own an ebook in two languages. Is there a software that combines them to one bilingual ebook?
  
  I suppose this shouldn't be hard, as a basic translator can figure out which paragraphs/sentences are translations of each other, and can then put them (in some sense) next to each other. That's all I want from my output.
upvoted_answer: I suppose this shouldn't be hard, as a basic translator can figure out which paragraphs/sentences are translations of each other, and can then put them (in some sense) next to each other. 
  
  
  Actually, it's not that easy, because original and translated documents often have different paragraph/sentence counts.
  
  Even sophisticated CAT tools don't perfectly align translated documents.  
  
  AFAIK, the only Open Source alignment tool is LF Aligner, which is based on Hunalign.