aspell check individual paragraphs

Hi,

I am searching for info on how to make a aspell check of individual
paragraphs inside of vim.

I edited and spell-checked a large file, and recently made more
changes at certain paragraphs, I don't want to run aspell check from
the beginning again, specially if it involved lots of tags or
formulas.

I use vim and aspell on Ubuntu, except save the paragraphs in another
file. Is there a simple way to aspell-check paragraphs interactively?
Tell aspell to check from line number A to B, or selected section
only? Also don't want to use aspell -a.

Thanks!