I was told by a friend that at a congregation in Costa Rica a black brother giving a talk continually pronounced the word Niger as, well, you can probably guess how he mispronounced it (yes, the "N" word). One of the elders pulled him to the side and told him the proper pronunciation. Ouch!
The brother who studied with me, years ago, and he was only a few years older than me, corrected me when I said the word Habakkuk. He told me that the correct pronunciation was "Hab-back-a-nock". I was so timid at that age that, since he was the elder, I just said okay (I knew that it wasn't really pronounced that way).
Now, as if it wasn't bad enough that he should correct me whenever it was he that was in error, he raised his hand at the KH when the subject of Habakkuk came up and informed the whole congregation that the correct pronunciation was "Hab-back-a-nock".
I don't know if anyone corrected him after the meeting that night, but if you should ever run into a JW who pronounces Habakkuk as Hab-back-a-nock, tell him I said "hello".