1. ad ionizing radiation and dna the best analogy I have ever heard was from Karl Z Morgan : ionizing radiation acts towards cell DNA like a shotgun going off in a library. Most shots miss the letters, and when they take out a letter, in most cases, the librarian will understand what was there. But in some cases the meaning cannot be reliably ascertained and the dna cannot be reliably replicated. Hence the linear dose-response hypothesis. The "librarian" may not be quite awake sone nothing much ever happens , or very busy , so the cell repair mechanisms may possibly respond in an non-linear fashion. The jury may still be out on this, but my knowledge of these matters is ancient and always was rudimentary.
The result may be innocuous, illness or evolution. The shots may be few and far between like background radiation or more targetted. (remember the square root law of distance). So, for the Thorium elements in a lens, do not fuse them with your glasses and wear the contraption around the clock, but at the usual distance, not that much extra radiation.
2. Linguistics is rather interesting. I assume that some of American idiom hails from "fossilized" English. The US- pronounciation of "R", however sounds like Irish English, so maybe the navvies set the tone?. "Fossilized" French certainly exists in North America, -as I discovered once when paddling up to the Canadian end of lake Memphremagog.
You will find a treasure trove of discussions on how various languages and genetypes moved around the world at dna-forums.com. Especially erudite, "Jean"s the peopling of europe, but also heated discussions on where the Celts came from, whether Normans were cryptofrisians etc. DO have your scientific citations and references in order if you venture into discussions there.
p.