I think the point Simon made was certainly true in the days of Frederick Franz, when Watchtower articles used such words as "revivify" (and we all had to consult the Oxford Dictionary to confirm that there was indeed such a word in the English vocabulary!).
When I first started attending Kingdom Hall meetings in the late 1960s, the JWs were fastidious about grammar and pronunciation - certainly in the congregation I was with, anyway. However, towards the end of my time with the JWs (in the late 1980s), there seemed to have developed an absolute aversion to using any words "bigger than marmite", with a clear preference for those of single syllables. Together with that, it was no longer a punishable offence to make a grammatical error in ones speech.
Since breaking with them in the mid-1990s, I have had very minimal contact with the JWs, and have read very little of their printed matter.
Vienne may well be right.