This reminds me of a story I was told while I was working in the Netherlands and failing miserably to learn to speak Dutch.
The story went that during WW2 amongst the Dutch resistance and partisan groups, the acid test for being a "het inheemse Nederlands" (native Dutch), was the ability to pronounce the word Scheveningen.
The fact that amongst the group party to the discussion, there were native Dutch speakers from Den Haag, ApelDoorn, Harderwijk, Maastricht, Groningen and Gent(*), and many of them would have been condemned as Nazi spies by their varying pronounciations of the town's name, rather diminished the impact of the shibboleth.
Oh darn. Now I've gone and and provoked Godwin's Law.
(*) For those who don't know, Gent, is in the Flemish speaking part of Belgium. Flemish is very similar to Dutch, suffiently similar that speakers of the two groups generally have no problems communicating even on quite deep and intellectual subjects. However, the biggest difference (as far as I am competent to judge as a non-speaker of either) is the pronounciation.
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
Lingua non convalesco, consenesco et abolesco. -- Rule 1 has a caveat! -- Who broke the cabal?
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.