Pixelbook No LibreOffice Thesaurus

Hi everyone,

I am running Penguin Linux - a Debian variant on my Pixelbook (Chromebook). I successfully installed LibreOffice, and it is the United States version of same. The thesaurus, however, is grayed out under Writing Tools and nothing I can think of allows me to use the thesaurus as I type. Does anyone know how I can properly deploy the thesaurus? Thanks so very much.

It looks Libreoffice has only the US English thesaurus, and the AU English; I am using British English, and can’t access the Thesaurus unless I switch to US English. I am using Xubuntu 18.04, and in the official repositories there are a number of Mythes Thesaurus for different languages, but not all English local ‘dialects’ are covered.