Yes, sorry I forgot to specify, system language is US English. I do have the “English (United States)” dictionary selected in the Scrivener Corrections settings.
I did install Scrivener using the .deb. And yes I did use the guide that you have linked to.
I notice in edf’s post ([url]A Mostly Complete Guide to Installing Scrivener on Linux]) the paths for Scrivener look like /usr/local/LiteratureAndLatte/lib but on my system it is /usr/share/scrivener/lib – did I somehow install Scrivener in the wrong place?