A myth (or story with teachings) within the Quaker world, is success in business followed the early period of persecution (special prosecution). Enough members of the nobility, celebs, had publicly joined to make the sect respectable even in Court (somewhat like Scientology in that way). At that point, a reputation for plain truthful speech would get you far, as this quality was sorely missing in business and gave the practitioner, the Friend, an edge.
However, what is "plain speech"? Quakers prided themselves on pretty much purging their grammar of notions of class. The familiar "you" (back then "thou") was used towards everyone. We should pause to remember how many languages, outside of English, inflect the "you" according to rank in society. The grammar tells you your place, which helps keep it unconscious.
English becomes peculiarly frustrating in that it fails to obey the rules, is not inflected to read "inferior speaking to a superior", not by default. You have the Quakers to thank for that to some degree. They pioneered a kind of egalitarianism that was highly compatible with the spread of democracies and their rhetorical bastions.
But speech may be classist in other ways. An accent packed with dodgy euphemisms that seems to not "cut through it" has the aspect of "not plain". What will it take for Quakers to stay plain in both dress and speech? I don't think it means unappreciative of highly fanciful. There's a unity of opposites here.
The plainness is to allow the bigger moves to become apparent. People willingly suspending their individuality to help some "will" be expressed: that's where things may go awesomely wrong or awesomely right depending. In making a movie, the stars work together to create a story as conducted through a director, screenwriters and so on. The whole is not just some sum of the parts. Or: "summation" is not just the simple operation we think.
Musical events have this channeling ouija-like ability, other shared works of art, even TV series (coming out in "serial" is how Charles Dickens made a living -- back when people relied on their own imaginations instead of telecasts).
If you come across a Quaker cussing, talking like a pirate, swearing a blue streak, is that "plain speech"? Should this man or woman be eldered? She or he may be an elder. Perhaps a psychopath? Perhaps, but since when are we called to serve as judge before Judgement Day?
My definition of "plain speech" would encompass the standard est vocabulary for example (a late 1900s philosophy talk and workout), easily, wherein metonymy (synecdoche more specifically) was sometimes used to equate people with their anal orifices.
No, this was a real philosophy, and not necessarily lobotomized (unintelligent) just because crass or crude. More just TV-14 for language, sex and violence (people told their true to life stories, though the emphasis was on Logic more than History, in the Hegelian sense).
I saw Tommy Chong and his wife in a live performance last night at Helium, one of Portland's many comedy clubs. I learned from them too. I found them plain spoken enough. More than many, lets put it that way. I was happy to bask in their non-hypocrisy, far from the euphemisms and perpetual pussy footing of many a meetinghouse Friend, more straitjacketed by their matrix.
Tonight it was The Walking Dead at The Bagdad. I saw at least one other member of the meeting there. I won't officially propose this AMC tele-drama for the syllabus though (the Adult Education program), at least not for the "meetup" format, as it's a serial, still ongoing, so a bigger commitment in terms of time.
Our practice is starting with the "all in one go" event, though Lord of the Rings is a trilogy, and I hear they're extending Star Wars as well. I say lets start with bite size and work up to it. If a group wants to peel off and do a series, fine, but I'm not volunteering to convene such a thing.