UBUNTU 18.04
Spell libraries hunspell-en-gb and hunspell-en-us are installed.
Spell check does not find errors.
When I open the Tools/Spelling/ dialog, Writer runs spell check, and finds no errors (even though there are errors).
The Text Language selection button says [None]. Options under the button are English UK and English US, each ticked.
However when I choose either option, the field returns to None.
The document font (at the bottom of the page) shows English US.