I am using Ubuntu 16.04 LTS and LibreOfice 5.1.4.2, and Spell Check does not work. How can this be corrected?
Running the hunspell-en-gb installer from command line terminal ( sudo apt-get install hunspell-en-gb ) worked for me too running Libre Office Writer on Trisquel 8.0 LTS Flidas GNU/Linux (based on Ubuntu 16.04 LTS) and wishing for English(UK) spell check. When I exited and restarted Libre Office spell check was working correctly with propah UK English.
In Debian, spellchecking for LibreOffice is provided by the ‘hunspell’-packages. Should work in Ubuntu, too.