Question: Out in the former state of Utah, near where the Old Salt Lake ruins are, a group of scholars and students from the New Jerusalem University are on an exploration mission. They have heard, from an unknown but (maybe) reliable source that an old Fallout Shelter is out there. They search all day until they find it. They ask, or rather force, some slaves to break down the door, and they are able to get in. 

The Fallout Shelter, though littered with skeletons, is full of valuable knowledge from before WWIII. The paper they used in the Old Times was super powerful, and never rotted, at all. Most of the notes the found were just grocery lists and etc. but they do find a blueprint which talks about some machine powered by that mystical force, the “electron” if I remember correctly. 

There is just one problem. The apocalypse was 800 years ago, and since that time New English (The language they speak in the present) is totally different from Modern English. So, what might be a plausible reason for why the college kids could read Modern English?

Answer: 
Languages tend to develop fastest in cities, where lots of people meet and develop new words and new grammar. Outside the cities, especially in isolated communities, language change is slower. There are parts of Sardinia that have an Italian dialect that would probably be intelligible to the Romans. If this is the case it may be that a slave can read what the intellectuals cannot.

*Modern English is a foreign language to the intellectuals of New Jerusalem, but out in the wilds of Utah, among the backwoodsmen, you will still find families who speak a language that, while it isn't classical English, could be understood by a person from the times before the war.* 

*Among the slaves is LeVerl, and he grew up in an old isolated family (before his capture and enslavement), and while he has since learned to speak New, he still knows the language that his mother learned from her father. To the scholars’ surprise he can read the old texts.*
**Children's books**

If the daily paper is that long lasting (ours isn't). Some books should also survive. If some of those are children's books good guesses about what words mean can be made. If a full children's library was available it should be possible to follow the same steps as learning to read.

**Labeled Goods**

Many products are labeled. If the scientists are good they may be able figure out what had been in the packages and learn names and some other words that way.

**Secondary Translations**

A say Navajo or Chinese dictionary might be linkable to known languages or other archaeological sites' work. The Bible specifically is printed in a large number of languages and reasonably likely to be included in caches and has a prominent symbol (cross) to aid in linking between versions. Even if it becomes heresy it may have significant scientific value.

**They don't need to read**

Seeing a system that only time and not bombs or looting destroyed might give valuable hints. Knowing that water or steam turned big wheels, or that copper was made into wires and often coiled could be a big step towards recreating the technology.