It is heard when people say something like "In his speech he referenced the effect of climate change on the arctic." instead of "...he referred to the effect...".

I tend to think that the "self-" is a sloppy redundancy that is intended to somehow reinforce the fact that an individual has confessed rather than being accused. The term is usually used when someone admits to something a bit embarrassing, silly or unexpected - "The English professor is a self-confessed lover of romance novels." The meaning would be unaltered if one said "The English professor is a confessed lover of romance novels." As has been stated, no one but the professor could have done the confessing.

The question is not one of grammar, but of usage. Hanged is the traditional usage but hung is not incorrect.

As a Canadian I was always puzzled by the "oot and aboot" thing. When, after many years, I finally did a very careful analysis of the sounds I discovered that I, and I assume I am too untypical, really turn the "ou" into two sounds. It comes out as something like "owoot". I notice that the final position of the lips is the slightly pursed extended position of the "oo" sound.

My daughter goes to a international school with many Americans and they love to get her to say "oot and aboot".