lucy24 - 2:12 am on Feb 8, 2012 (gmt 0)
You're going to need to add the language-specific parts yourself, but from the RegEx side:
You have to capture the entire text block in one go, so you can change
^blahblah blahblah blahblah$
blahblah blahblah blahblah
instead of treating each word as a separate unit.
If a single text block contains multiple paragraphs-- as your reference to <br /> implies-- then you've actually done the work already. Don't just insert a break: insert a break and a group of spaces at the same time.
I assume there's some compelling reason why you can't use
Paragraphs would make the whole problem go away, because you could then throw in a line or two of CSS to indent them all.