I've had to answer this question so many times I should probably just prepare a form letter.
In the summer of 1973, when I was 14, the JWs called at my house and left the Truth book. They tried to get me interested in a study, but I decided I'd rather do my own independent investigation. I became intrigued when I found out about the expectations concerning 1975, but was never in any danger of converting from Catholicism. The nuns at my high school raised an eyebrow when they saw God's Kingdom of a Thousand Years Has Approached sitting atop a pile of my textbooks, but were otherwise unconcerned. Not much can ruffle a Josephite's feathers, that's for sure.
There was a family from my church which did convert en masse. One day the girl who was my age was in class; then she wasn't. I later saw her at the Kingdom Hall when I went to check out the Sunday "public talk" and Watchtower study. There were also a couple of JW families in my immediate neighborhood. I played with one set of JW kids when I was very young, but that was only an occasional thing.
I began to collect the books, booklets, and other literature. It was cheap and easy, since they used to have catalogs and do direct sales. The only unwelcome price was the inevitable follow-up visit. But I didn't really take off as a collector until I ran across The Harp of God at a library book sale. It never occurred to me that I could actually find these old books so cheaply! I began to scour every sale and musty old bookstore for more, and pretty soon I was on my way.
So, my familiarity with the lingo comes from many years of reading the publications on-and-off, in addition to outside books. I have a collection which ranges from Russell's time through present-day publications, and a pretty wide selection of non-WT books about JWs, ranging from indifferent to hostile. I'm a never-was, but I've picked up on some of the phrasing and catchwords. I actually cringe a little when I hear people refer to someone as "a Jehovah Witness" instead of "one of Jehovah's Witnesses."
My interest in religion isn't confined to JWs, but that's the bulk of what I've collected. I love books in general, which is why I got into the bookselling business. It doesn't generate a lot of income for me; at this point it's been more of a luxury or hobby. But I do get to work around books and book people, which is lovely.
Thanks for asking!
Cathy