So far I've translated about 2000 pages out of ten languages that I don't speak. Here are my top three problems:
1. Though most of what I translate is technically in the modern form of these languages, the spelling isn't. If I actually spoke the languages, I could pronounce the words out loud and them figure out.
2. Some writers are overly flowery or just plain bad stylists. This often defeats the available grammar of my translation programs leaving me to bludgeon my way through in short phrases or even word-by-word.
3. Actual typos in the source material. I figure out the grammar part and start entering every possible variation I can into various dictionaries and none of them is a word. Finally, I realize they weren't minding their P's and Q's and everything is fine.
Bonus observation: About three years ago I noticed something odd about the way the long and short S was used in some documents. There two sets rules for their use. The difference centers on when to use the short S. In some pieces they would be using one set of rules and suddenly shift to a different set. At first I thought they didn't have enough pieces of long S type to do some sheets and shifted over to the rules that allowed more short S's for those sheets. Just last week I finally figured out what was really going on. I was reading a monthly journal that probably needed to be assembled and printed fairly quickly. The printer was a fairly large house and must have had more than one typesetter working in the shop with some of them using one set of rules and some using the other.
I'm writing this to avoid working on a Latin document that is rife with sin #2. Get back to work, John.