For example, with stock Russian dictionary: Межгала*т*тическую -> Межгалактическ*ий* (!), *Вне*галактическую (!!), etc. мес><ные -> *при*месные, *мало*весные In both cases correct variants aren't EVEN offered! As you see, even TRIVIAL misspellings of 1 misspelled or missed letter FAIL to give correct suggestion. It's UNACCEPTABLE.
I don't know which russian dictionary you are using, but you should contact russian dictionary maintainer(s), for the LibreOffice developers don't work on dictionaries. This is external stuff. http://extensions-test.libreoffice.org/extension-center/russian-spellcheck-dictionary.-based-on-works-of-aot-group http://extensions.services.openoffice.org/en/dictionaries Spelling suggestions are made by Hunspell, so you should read the documentation to help to improve it if you can: http://sourceforge.net/projects/hunspell/files/Hunspell/Documentation/ Use the command REP and TRY, which are not really used in the russian dictionary in which I had a look.