Consider the following problem: you have one text translated into two languages,
First line // Unua linio Second line // Dua linio
and there's a need to display them side by side using all available space, make them accessible to search engines as separate paragraphs and allowing separate selection. That way if someone does a search for "Unua linio dua linio" they see exactly that paragraph without text from the first creeping in.
I've considered using tables but not sure how it will affect search engine indexing, it's also not very "correct" to split lines in a paragraph into rows. Considered putting one paragraph on the left side and the other on the right and shifting them vertically so it goes like this:
First line Unua linio Second line Dua linio
but cannot devise the proper HTML markup for that.
Edit: another (ideal) example would be
Really really long line in a paragraph that spans two lines Translation of this really long line Second line Translated second line