To continue on the random language use theme: I've noticed recently that I seem to have completed a gradual transition from being a ‘moreover’ person to being a ‘furthermore’ person.

Ten years ago I was a maths student. ‘Moreover’ is part of standard mathematical idiom. You find it a lot in statements of theorems: ‘there exists exactly one thingy satisfying these conditions, and moreover it is the limit of the following sequence’. So, naturally, hanging around a lot of mathematicians and dealing with a lot of theorems and proofs and mathematical writings, I got used to using ‘moreover’ when I had a concept of this nature to express.

These days I don't hang around with that many mathematicians any more, and I do hang around with IWJ who tends to say ‘furthermore’ a lot, particularly often (and particularly loudly) when he's ranting about some company being stupid: ‘they made this error, and that error, and furthermore refused to give a refund’. So my idiolect has gradually adapted so that I now say ‘furthermore’ where I might once have said ‘moreover’.

At some point during this transition, a few years ago, I noticed that I was willing to use both words but felt them to have different connotations and emphasis. I would tend to say ‘moreover’ if I was talking about good or useful things (‘and even better…’), but ‘furthermore’ if I was talking about bad or annoying things (‘and even worse…’). It seems likely to me that this derived from the difference in usage: mathematical theorems are good and useful things because they provide you with knowledge, and ‘moreover’ tends to prefix an extra piece of useful knowledge, whereas Ian's rants tend to be about a sequence of annoying things of which ‘furthermore’ introduces an even more annoying one.

I consciously tried to retain this usage once I'd noticed it, because I thought it would be rather nice to encourage a subtle difference between two otherwise redundant words, but it doesn't seem to be happening any more: even in ‘good’ contexts I now find I naturally say ‘furthermore’. Shame.